Patent ID: 12203225

DETAILED DESCRIPTION OF EMBODIMENTS

While embodiments of the inventive concepts are illustrated and described herein, the device may be embodied in many different configurations, forms and materials. The present disclosure is to be considered as an exemplification of the principles of the inventive concepts and the associated functional specifications for their construction and is not intended to limit the inventive concepts to the embodiments illustrated. Those skilled in the art will envision many other possible variations within the scope of the present inventive concepts.

Embodiments of the inventive concepts are described herein in the context of an autonomous single roller surface compactor. It will be appreciated, however that the inventive concepts described herein can be applied and/or implemented in many different types of surface compactors and other construction vehicles. Turning now toFIGS.1,2and3, construction vehicle in the form of a single roller surface compactor machine100is depicted. In particular,FIG.1is a perspective view,FIG.2is a side cross-sectional view andFIG.3is a front cross-sectional view of a single drum surface compactor machine100.

As shown inFIGS.1to3, the surface compactor100is a rolling compactor provided with a single roller105having a split roller configuration. In some embodiments, the roller105includes first and second drums110A,110B that are attached via a rotational coupling175that permits independent rotation of the first and second drums110A,110B along a common axis of rotation155. Split roller configurations are known in the art. In some embodiments, the surface compactor100may be a remotely controlled or autonomous vehicle.

In operation, the roller105propels the surface compactor100along a substrate to be compacted, such as asphalt, earth, rocks, etc. As the compactor100moves across a substrate, the roller105applies a compaction force to the substrate.

As shown inFIGS.1to3, the rolling compactor100is provided with compacting surfaces in the form of first and second drums110A,110B that are cylindrical in shape. The outer circumferential surfaces of the drums110A,110B contact the substrate that is to be compacted. As the roller105propels the surface compactor100along the substrate, the drums110A,110B exert a heavy compacting force on the substrate.

According to some embodiments, the roller110is driven by one or more electric motors positioned within an interior cylindrical space defined by the first and second drums110A,110B. In the embodiments illustrated inFIGS.1to3, the compactor100includes first to fourth electric drive motors140A,140B,140C,140D mounted within a cylindrical interior space defined by the first and second drums110A,110B. Although four drive motors are illustrated, more than four or less than four drive motors may be included in some example embodiments. The first and second electric motors140A,140B are mounted on a first support bracket135A in the first drum110A, while the third and fourth electric motors140C,140D are mounted on a second support bracket135B in the second drum110B. Each of the first to fourth electric motors140A to140D is coupled, for example, via a drive chain142A,142B, drive shaft, drive belt, direct gear drive and/or other drive mechanism, to a respective drive wheel150A to150D, such that each electric drive motor140A to140D causes the respective drive wheel150A to150D to turn.

The first and second drive wheels150A,150B are mounted to the first support bracket135A, while the third and fourth drive wheels150C,150D are mounted to the second support bracket135B. The first and second drive wheels150A,150B are positioned to be in contact with an inner surface of the first drum110A, while the third and fourth drive wheels150C,150D are positioned to be in contact with an inner surface of the second drum110B. In some embodiments, the first and second drive wheels150A,150B are positioned to be in contact with a first track175(FIG.4) provided an inner surface of the first drum110A, while the third and fourth drive wheels150C,150D are positioned to be in contact with a second track175(FIG.4) provided an inner surface of the second drum110B. The track may include a rail, channel, slot, gear teeth, or any other suitable feature that maintains contact with the drive wheels150C,150D.

The first and second drive wheels150A,150B may be circumferentially offset from one another, while the third and fourth drive wheels150C,150D may be circumferentially offset from one another. For example, as illustrated inFIG.2, the first and second drive wheels150A,150B may be circumferentially offset from one another by an angle of about 60 degrees.

The first and second drive wheels150A,150B may in some embodiments be spring biased against the interior surface of the first drum110A, and the third and fourth drive wheels150C,150D may be spring biased against the interior surface of the second drum110B so that the drive wheels maintain a firm contact on the interior surfaces of the respective drums. In some embodiments, the drive wheels150A-150D may be biased against the drums110A,110B using leaf springs, coil springs or any other suitable spring mechanism. In yet other embodiments the drive wheels150A-150D may be held in place against the drums110A,110B using only gravity. In still other embodiments the drive wheels may engage respective circular tracks on the interior surfaces of the drums110A,110B.

Accordingly, when the first and second drive wheels150A,150B are driven by the respective electric drive motors140A,140B, a torque is transmitted to the first drum110A, causing the first drum110A to rotate. Likewise, when the third and fourth drive wheels150C,150D are driven by the respective electric drive motors140C,140D, a torque is transmitted to the second drum110B, causing the second drum110B to rotate.

It will be appreciated that the first and second drive wheels150A,150B may be driven independently from the third and fourth drive wheels150C,150D, so that the first drum110A and the second drum110A may be rotated independently of one another by the drive wheels150A to150D. For example, the first drum110A and the second drum110B may be rotated at different speeds and/or in different directions by their respective drive wheels. Allowing the drums110A,110B to rotate at different speeds may reduce shearing forces that may be transmitted to the substrate when the compactor100is driven in a curved path over the substrate.

The compactor100further includes a counterweight130positioned within the cylindrical interior space defined by the first drum110A and the second drum110B. The counterweight130may provide a major portion of the weight of the compactor100. For example, in some embodiments suitable for heavy duty operation, the counterweight130may have a weight greater than 100 kilograms, and in further embodiments greater than 500 kilograms. The counterweight130may be attached at opposite ends thereof to the first support bracket135A and the second support bracket135B, which suspend the counterweight130in a spaced relation to the drums110A,110B.

In some embodiments, the first to fourth drive wheels150A to150D may bear at least part of the weight of the counterweight130. For example, as illustrated inFIG.2, since the drive wheels150A and150B are positioned on the support frame beneath the counterweight130, they may support at least some of the weight of the counterweight130. In other embodiments, one or more of the drive wheels may be positioned such that they do not bear any of the weight of the counterweight130. For example, in some embodiments, one or more of the drive wheels150A to150D may contact the inner surface of the drum110A,110B above the counterweight130.

A first non-driven support wheel160A is attached to the first support bracket135A, and a second non-driven support wheel160B is attached to the second support bracket135B. The first and second non-driven support wheels160A,160B may rotate around a common axis of rotation that is parallel to the axis of rotation of the drums110A,110B. The first non-driven support wheel160A is positioned in a lower portion of the first drum110A, and rests against a lower portion of the first drum110A. Likewise, the second non-driven support wheel160B is positioned in a lower portion of the second drum110B, and rests against a lower portion of the second drum110B. The first and second non-driven support wheels160A,160B thereby carry a major portion of the weight of the counterweight130and the first and second support brackets135A,135B, as well as the weight of other items supported by the counterweight130and/or the first and second frames135A,135B, as discussed below. The weight carried by the first non-driven support wheel160A is transmitted directly to the lower portion of the first drum110A, while the weight carried by the second non-driven support wheel160B is transmitted directly to the lower portion of the second drum110B. The non-drive support wheels160A,160B may collectively carry a major portion of the weight of the counterweight130, while the drive wheels150A to150D may collectively carry a minor portion of the weight of the counterweight130. In some embodiments, the first and second non-driven support wheels160A,160B may ride in or on channels175(FIG.4) provided on the inner surfaces of the first and second drums110A,110B.

Referring toFIGS.2and3, the counterweight130may have a generally semi-cylindrical shape that fits within a bottom portion of the cylindrical space defined by the first and second drums110A,110B. Because the counterweight130accounts for a major portion of the total weight of the compactor100, a center of gravity of the compactor100may be located substantially beneath the central axis155of the drums110A,110B.

Still referring toFIGS.2and3, a number of other components of the compactor100may be mounted on the counterweight130. For example, an engine210and a generator220may be mounted on and supported by the counterweight130. The engine210may include a drive shaft215that drives the generator220. The generator220responsively generates electric power that is used to drive the drive motors140A to140D. An electronic control unit (ECU)260controls the individual speeds of the drive motors140A to140D.

A vibration mechanism may be provided within the cylindrical drum. The vibration mechanism is configured to vibrate the counterweight and thereby the entire drum to improve the compaction rate of the substrate. In the illustrated embodiments, the vibration mechanism includes a vibration motor230mounted on the counterweight130. The vibration motor230includes an output shaft235and an eccentric weight240attached to the output shaft235. When the vibration motor230spins the output shaft235and the eccentric weight240, a vibrational force is applied to the first and second drums110A,110B through the counterweight130. In this manner, the first and second drums110A,110B may be vibrated during operation of the compactor100. Operation of the vibration motor230may also be controlled by the ECU260. Other vibration mechanisms may be provided instead of or in addition to the vibration mechanism illustrated inFIGS.2and3.

A compactor100as described herein may operate autonomously and/or through remote control. That is, the compactor100may not be attached to a cab or to external drive wheels, but instead may be a self-contained unit as shown. In other embodiments however, the compactor100may be attached to other elements, such as external wheels for stability, an operator cab, etc.

FIG.4is a block diagram of an ECU260for a compactor100according to some embodiments. In particular, the ECU260may include a microprocessor or microcontroller circuit310(or simply processor circuit310), a memory330, a wireless interface320, and an input/output (I/O) interface340. The processor circuit310may communicate with the other elements of the ECU260through a system bus, I2C connection or other connection. In some embodiments, the system bus may conform to the J1939 communication standard for vehicles. Other protocols, such as CANopen and LIN may also be used. The memory330may include a volatile or nonvolatile RAM, ROM, EPROM or other suitable storage. The wireless interface320enables the ECU260to communicate with external devices, such as an external remote control device, sensors, telemetry devices, etc., using a wireless communication protocol, such as Bluetooth, WiFi, etc. The I/O interface340, which may for example include a universal asynchronous receive transmit (UART) interface, enables the ECU260to communicate with other electronic elements of the compactor100.

In some embodiments, the electrical system of the compactor100may include separate DC and AC components. The generator220may be AC or DC generator that generates an AC voltage and/or a rectified DC (12V, 24V or 48V) voltage for powering various subsystems in the compactor100. A battery may also be provided to assist in startup of the engine210and/or the vibration motor230.

FIG.5Ais a block diagram that illustrates electrical interconnections between an ECU in the form of an ECU260and other elements of a single drum surface compactor100according to some embodiments. As shown inFIG.5A, the ECU260may be electrically connected to and control operation of the engine210, the generator220, the vibration motor230and the drive motors140A,140B (drive motors140C and140D are not illustrated inFIG.5A, but may be present in the system). The ECU260may also be connected via a wireless interface360to a remote control (human-machine interface, or HMI) terminal350that can be used to remotely control operation of the compactor100.

The ECU260is further connected to a DC/DC converter for supplying 12V power to an on-board electrical system and a DC power controller360for distributing DC power to various subsystems in the compactor100as described in more detail below. The compactor100may have a hybrid power system that generates power using both an internal combustion power source, such as diesel power, using the engine210and an electrical power source. Accordingly, an electrical power supply165including a supercapacitor or supercapacitor bank and/or an electrochemical battery may also be coupled to the control circuit.

The compactor100further includes a DC power controller370coupled to the ECU260that controls distribution of DC power to load systems within the compactor100.

The compactor100further includes one or more sensors372coupled to the ECU260for providing real-time data regarding the operating condition and/or environment of the compactor100to the ECU260. The sensors can be mounted externally or integrated into electrical components of the ECU260, and may include sensors such as one or more current sensors to monitor current supplied to/from various subsystems and one or more voltage sensors to monitor the DC voltage supplied to/from various subsystems. The current/voltage sensors may be integrated within power/motor controllers and/or inverters in the electrical system.

The compactor100may further include one or more state of charge sensors to monitor a state of charge of a supercapacitor and/or electrochemical battery.

The compactor100may further include a motor speed sensor at each motor. In particular, a motor speed sensor may be positioned at each motor's shaft and may be integrated in the motor as a 6-step Hall angle sensor.

The compactor100may further include a gyroscopic/inertial measurement unit for balancing the drum110and determining the actual inclination of the ground beneath the drum.

The compactor100may further include a fuel level sensor, one or more temperature sensors to obtain temperature readings of the substrate and/or the ambient temperature, a GPS device for determining/tracking the compaction path and calculating the overall energy balance, and one or more laser sensors/reflectors (mounted on compactor or paver) to help guide/track the compactor during the compaction process.

FIG.5Bis a block diagram that illustrates elements and interconnections of the electrical system within the compactor100according to particular embodiments in more detail. As shown inFIG.5B, the engine210, which may be a diesel-powered engine, such as a Kubota 03 series engine capable of generating 18.5 KW of power, drives the generator220via a drive shaft212. It will be appreciated that other types of combustion engines, including gasoline powered engines, propane engines, or liquid natural gas engines, may be used instead of a diesel engine. The generator220generates a three-phase AC output which is provided to a DC power controller370. The DC power controller370converts the AC power to DC and supplies 48V DC power to a DC power bus315. The engine210, the generator220and the DC power controller370are controlled by the ECU260. A 12V battery214provides start-up power for the engine210and initial power for the control circuit260. The DC power controller370may be implemented using, for example, an ACS48L90 motor controller by Inmotion Technologies, AB.

The drive motors140A,140B and the vibration motor230are connected to and draw power from the DC power bus315via respective motor controllers355A,355B,355C, which may be implemented using, for example, ACS48M45 motor controllers by Inmotion Technologies, AB. A DC/DC converter157is connected to and draws power from the DC power bus315to generate a 12V DC supply voltage for driving the 12V electrical system of the compactor100. Drive motors140C and140D are not illustrated inFIG.5B, but may be present in the system along with associated motor controllers (not shown).

A hybrid electrical power system is provided by means of an electrical power source, such as a 48V supercapacitor bank and/or electrochemical battery165. The electrical power source may be provided with a plug-in charging adaptor365including a pre-charge resistor (not shown) for off-line charging. A shunt resistor (not shown) may be provided between the DC power bus315and ground.

Referring toFIG.6, an autonomous single drum compactor100A including an ECU260is illustrated. As shown inFIG.6, the single drum compactor100A may communicate via a wireless connection360with a control panel (HMI)350and/or with another autonomous single drum compactor100B, as will be described in greater detail below.

FIG.7is a block diagram illustrating various functional subsystems of an electrical system of a compactor100according to some embodiments. Referring toFIG.7, an electrical system of a compactor100includes a hybrid power generation subsystem400including an internal combustion power source410including, for example, a diesel engine210and a generator220that supply electrical power generated via fuel combustion, and an electrical power source420including a supercapacitor and/or battery bank165that supply electrical power from a store of chemical or electrical potential energy. The power output by the hybrid power generation system400is supplied through the DC power controller under control of the ECU260to a plurality of electrical/electromechanical load subsystems including a traction power subsystem430, a vibration subsystem440and an electronics power subsystem450. The traction power subsystem430includes the drive motors140A to140N and related motor controllers355A,355B (FIG.5B). The vibration subsystem440includes the vibration motor230and related motor controller355C (FIG.5B), and the electronics power subsystem450includes the DC/DC converter157.

According to some embodiments, the ECU260obtains a planned operating profile of the compactor100and generates a predicted power expenditure schedule for the compactor100based on the planned operating profile. The ECU260determines, based on the predicted power expenditure schedule, whether a predicted energy expenditure of the compactor100will exceed an available energy of the compactor. If the ECU260determines that the predicted energy expenditure of the compactor will exceed the available energy of the compactor100, the ECU260generates a modified operating profile and operates the compactor100according to the modified operating profile. In this manner, the ECU260may increase the efficiency of the compactor100by enhancing the power efficiency of the compactor100, which may make more efficient use of available power resources and/or may decrease CO2emissions by the compactor100.

Some embodiments attempt to optimize the power efficiency of the hybrid power system of a compactor100to provide more stable traction and continuous vibration of the drum110via rotation of an eccentric mass by the vibration motor230.

This may enable the compactor100to increase substrate compaction and/or gain power efficiency, which can decrease the emission of CO2to the atmosphere. Moreover, some embodiments may enable the operation of a compactor100to be more fully automated, which can help to avoid and common mistakes during the compaction cycle.

Conventional compactor machines are designed to meet an expected power load during compaction. If the actual conditions are different than was anticipated during the design of the compactor, the resulting machine may be underpowered, in which case the machine may have difficulty completing its assigned tasks, or overpowered, such as by oversizing the engine, in which case the efficiency of the compactor may be diminished.

In the first scenario (i.e., when the compactor is underpowered), the overall power of the system may be unbalanced between the vibration motor and the traction (drive) system, which can cause diesel engine choking in a peak power condition, which can either stop the compactor or stop the vibration. Some embodiments can help to address this problem by using a series hybrid system that can implement a prioritization and balance of the power system.

In the second scenario (when the compactor is overpowered), the diesel engine may not work in its optimal range, as the peak power demand may not happen often in the work cycle. This can decrease the efficiency of the compactor and may result in an increase of the CO2emissions. Moreover, larger, heavier engines tend to be more expensive and use more fuel, increasing both the initial and operating cost of the compactor.

Some embodiments of the inventive concepts may control a hybrid power system for a compactor so that the power system uses and stores only the power that is actually needed by the compactor. Some embodiments can properly balance the power between the traction (drive) system and the vibration system and calculate the overall power balance through an entire compaction process to achieve a high-quality substrate compaction.

Some embodiments described herein may be implemented within a hybrid power unidrum compactor system. However, it will be appreciated that some embodiments of the inventive concepts maybe implemented in other types of equipment. Some embodiments provide systems/methods that manage the overall energy balance and compaction path calculation for a compactor that makes the compaction process more efficient by using and storing only the energy needed to complete the planned task. Moreover, some embodiments direct and/or prioritize the energy flow inside the hybrid system, which can make the compaction process more stable and avoid power system malfunctions. Further, some embodiments of the inventive concepts can help automate the compaction process based on the energy balance, which can help to avoid common human mistakes during the compaction process. During the operation of the compactor, energy may be gained through regenerative braking during balancing/descending, and such energy can be stored in an electrical power system, such as in supercapacitors, for subsequent use by the compactor.

According to some embodiments, a compactor100can be controlled manually via an HMI terminal350and/or automatically via programmatic control by the ECU260. Manual control is done by an operator who sets operating parameters for the compactor100and may steers the compactor100via a joystick or other human-machine interface (HMI). Automatic control may be initiated and monitored via a display-based HMI such as a tablet that can be either mounted inside a paver ahead of the compactor and/or be held by the operator supervising the compaction process. In an automatic mode, the operating parameters of the task may be set before the start of compaction, and then the process may proceed automatically.

During the compaction process the control can be mixed (manual/automatic). Automatic control can be switched to manual and taken over by the operator, such as when the compactor traverses a hazardous area where very careful maneuvering is required, as in a path with a high angle of descent, curves, etc.

Before the beginning of a compaction process, using data provided by the sensors372, the ECU260determines the total available energy in the system, including both the diesel power subsystem and the electric power subsystem, taking into account the state of charge of the supercapacitor bank and/or the electrochemical battery165, the fuel level of the engine210, and the ambient temperature. The ECU then generates a planned operating profile for the process based on parameters set by the operator, including compaction speed (exact or range), vibration frequency/amplitude, maximum compaction time, compaction distance and width of the compaction path, substrate type, substrate temperature and substrate thickness.

In the automatic mode, the compaction distance and path width can be marked on a map using the HMI350display with GPS/laser sensor localization. Based on the data provided, the ECU260calculates the estimated path of the compactor, which becomes part of the planned operating profile for the process. Based on the planned operating profile for the process, the ECU260generates a predicted power expenditure schedule for the planned process. The predicted power expenditure schedule specifies the expected power expenditure over the time frame of the proposed process for each of the power supply subsystems of the compactor100based on the overall planned activity.

Based on the predicted power expenditure schedule and the amount of energy available in the system, the ECU260may provide feedback to the operator about whether the planned operating profile is feasible. The ECU260may provide proposed corrections/modifications to the planned operating profile if needed.

In generating the modifications to the planned operating profile, the ECU260may apply one or more of the following objectives. In particular, the ECU260may attempt to prevent a loss of traction power during the compaction process. For example, a high peak power demand for vibration or a long compaction distance can result in a situation in which not enough power is provided to the traction motors. Stopping the compactor100on an uncompacted asphalt is highly undesirable, as it can cause dents and asphalt waving that cannot be easily removed.

The ECU260may also seek to reduce CO2emissions by changing into full-electric mode when the overall power consumption is low (for example during static compaction with vibration disabled).

If the system cannot meet the predicted power demand, the ECU260may inform the operator and provide suggestions for prioritizing between traction power (for example to lower the speed/torque in certain segments) and vibration power (for example, to lower the vibration power demand in certain segments) so that the proposed operating profile is achievable.

If the electrical power subsystem420is not fully charged, the ECU260may suggest that it be charged via an external (plug-in) charger prior to the compaction process, as plug-in charging may be more efficient than charging via engine power and may decrease CO2emissions by the compactor100.

Based on the predicted power expenditure schedule and planned operating profile, the ECU260may suggest that the operator use another compactor in a tandem. If another compactor100is available, the compactor200may send a planned operating profile to the second compactor for the second compactor to follow.

Some examples of modifications to the planned operating profile of a compactor100are as follows. Such modifications may be made based on the control signals (manual control) or compaction path set before (automatic control) the operation. For example, the ECU260may modify the planned operating profile so that a first pass over the substrate is made static (no vibration). That is, the compactor100will automatically make the first pass without vibration to avoid moving of the asphalt (common when paver's pre-compaction not enough). In this case, full-electric mode may be preferred depending on the compaction path and other parameters.

In another example, the ECU260may check the temperature of the substrate. The compactor100may measure the temperature of the substrate and turn off the vibrations if the temperature exceeds a set range (e.g., a default 100-140° C.). If possible, the ECU260may switch the compactor100to full-electric mode.

In another example, the ECU260may cause the vibration to stop on compacted asphalt. The compactor100will turn off the vibrations automatically and switch to all-electric mode when it is on an already-compacted portion of the substrate. The determination of when the compactor100is on an already-compacted portion of the substrate may be made based on GPS data, temperature readings, etc.

In another example, the ECU260may cause the vibration to stop when compactor100stops. The compactor100will turn off the vibrations automatically and change into full-electric mode when the machine stops (by operator's order or emergency stop).

In another example, the ECU260may cause the vibration to stop when the compactor100changes path or direction. The compactor100will turn off the vibrations automatically when the machine turns and changes the compaction path or starts to compact in the reverse direction.

In another example, the ECU260may cause the vibration to stop when descending an inclined surface. The compactor100will stop vibration during a high angle descent and change into full electric mode with regenerative braking re-gaining some of the energy.

In some embodiments, the ECU260may continuously evaluate the planned/actual operating profile of the compactor100during the compaction process and provide real-time updates or recommendations to the operator via wireless communication. If the conditions of the compaction process change (for example actual higher power demand or control taken over by operator etc.) the ECU260may generate and transmit send suggested corrections to the planned operating profile to the operator.

In some embodiments, the compactor100may use regenerative braking (braking torque) done by electric traction motors when descending (also changing to full electric mode) or/and during balancing the drum that will supply energy back to the system (DC-link) and store it in the electrical power subsystem420, such as by storing the energy in a supercapacitor bank.

The electrochemical batteries in the electrical power subsystem420may include lithium-Ion batteries that can store the energy and maintain a more precise voltage range on the DC power bus315for a much longer time than a supercapacitor bank can. It will be understood, however, that while an electrochemical battery such as a Li-ion battery may be capable of storing more energy than a supercapacitor bank, a supercapacitor bank may be capable of supplying a higher peak power than an electrochemical battery.

The use of Li-Ion batteries can provide more possibilities for utilizing full-electric mode while prioritizing the energy flow within the system and reducing CO2emission. In some applications, the use of a Li-ion based energy source may eliminate the need for a diesel/combustion based energy source altogether.

Without a diesel engine, the range and power of the compactor100would be strictly limited, in which case the power management systems/techniques described herein would be even more important to the compaction process.

FIGS.8A and8Billustrate an example of dynamic power management in a compactor100according to some embodiments. Referring toFIG.8A, a compactor100traveling on a horizontal surface at a constant velocity may require 30% of the available power being generated by the power generation subsystems of the compactor100. However, when the compactor100moves onto an inclined surface, the power requirement may increase, for example to 60% of available power, to maintain the constant velocity.FIG.8Bis a block diagram illustrating control of the various power subsystems of the compactor100, including the internal combustion power source410, the electric power source420, the traction power subsystem430, the vibration subsystem440and the electronics power subsystem450. The flow of power to/from the various subsystems is controlled by the ECU260via the DC power controller370. The ECU260predicts power requirements of the compactor100based on the planned operating profile and determines how to efficiently generate power and allocate available power to meet the operating requirements of the compactor100. For example, while the compactor is on the horizontal surface ofFIG.8A, the ECU260may control the DC power controller370to direct 30% of available power to the traction power subsystem430. When the compactor is on the inclined surface, the ECU260may control the DC power controller370to direct 60% of available power to the traction power subsystem430. In some cases, power to other subsystems may be reduced to make the extra traction power available. Alternatively, the ECU260may cause the internal combustion power source410and/or the electric power source to supply more power so that power to other load subsystems does not have to be reduced to accommodate the increased power demands of the traction power subsystem430.

If the ECU260is unable to control the power subsystems to obtain the desired result (because, for example, there is not enough energy or power to complete a planned task, or a parameter required to complete the task is out of range), the ECU260may notify the operator via the HMI350of that fact and suggest possible changes to the planned operating profile. For example, continuing with the example ofFIG.8A, if the internal combustion and electric power sources410,420are unable to supply enough power to maintain the desired speed of the compactor100on the inclined surface, the ECU260may recommend modifying the planned operating profile to reduce the speed of the compactor100on the incline, to increase the amount or percentage of power being supplied by one or both of the power sources, to decrease the power supplied to another one of the load subsystems, etc.

FIGS.9A and9Billustrate an example of the use of regenerative braking. As is known in the art, regenerative braking occurs when the drive motors are used as brakes to dissipate kinetic energy of the compactor100. In regenerative braking, the drive motors are driven in reverse and electromagnetic energy is recovered from the drive motors. That is, when mechanical energy is applied to the drive shaft from an external source, a back-emf voltage appears at the terminals of the motor. This voltage can be used to charge a battery or supercapacitor. When the compactor descends an inclined slope as shown inFIG.9A, instead of allowing the potential energy of the compactor100to be converted into kinetic energy, the potential energy released by the compactor100is used to drive the drive motors, essentially operating them as generators. In that case, as shown inFIG.9B, DC power is supplied from the traction power subsystem430to the electric power source420under the control of the DC power controller370. Such power can be used, for example, to charge a battery or supercapacitor in the electric power source420. As illustrated inFIG.9A, regenerative braking can be employed whenever the drive motors are being used as brakes, such as when the compactor100is descending an incline or when it is balancing.

FIG.10illustrates operation of a compactor100that is executing a planned operating profile. In the example ofFIG.10, a compactor100follows behind a paver115that is paving an unpaved surface132. The compactor100follows behind the paver115on the paved substrate124an compacts the paved substrate124, leaving behind a compacted substrate122in its path. The compactor100may follow a pre-planned route and/or may be guided by laser guides projected by the paver115and/or via GPS signals received by the compactor100. A planned operating profile may take into account the length of the path along with any direction or elevation changes, as well as the nature and type of substrate being compacted.

FIG.11illustrates an example of a planned operating profile600of a compactor100along with a predicted power expenditure schedule610and a graph620of predicted energy usage based on the planned operating profile. As shown therein, according to the planned operating profile600, the compactor100will operate for 80 seconds in full electric mode at a speed of 5 km/h with the vibration motor off. After that, the compactor100will operate for 400 seconds in hybrid diesel/electric mode at a speed of 5 km/h with the vibration motor on. Finally, the compactor100will operate for 30 seconds in full electric mode at a speed of 10 km/h with the vibration motor off. Based on the planned operating profile and the sensor data collected by the ECU260or other data provided to the ECU260, (e.g., ambient temperature, substrate type, temperature and thickness, etc.), the ECU generates a predicted power expenditure schedule610that specifies the amount of power generated or consumed by each of the subsystems at all relevant times covered by the planned operating profile600. (In this example, power consumed by the electronics power subsystem450is ignored).

The predicted power expenditure schedule610shows that in the first segment, the power generated by the internal combustion power source410will be 0 kW while the electric power generated by the electric power source420will be 4.0 kW, all of which will be consumed by the traction power subsystem430. In the second segment, 9.3 kW of power will be generated by the internal combustion power source410and 2.0 kW will be generated by the electric power source420. The traction power subsystem430will consume 4.0 kW of the generated power, while the vibration subsystem440will consume 7.3 kW of the generated power. In the third segment, the power generated by the internal combustion power source410will again be 0 kW. The electric power generated by the electric power source420will be 7.2 kW, all of which will again be consumed by the traction power subsystem430.

The graph620of predicted energy usage shows a level of diesel energy available422and electrical energy available424. The amount of diesel energy available is based on the fuel level of the diesel engine, while the electrical energy available is based on the state of charge of the batteries and/or supercapacitors in the electrical power source420. Appropriate safety/reserve margins may be added. Curve426shows the energy usage of the electric power source420over the course of the planned operating profile based on the predicted power expenditure schedule, while curve428shows the energy usage of the internal combustion power source410over the course of the planned operating profile. As shown in the graph, at the end of the planned operating profile, the internal combustion power source410is predicted to have used less than the available diesel energy422, but the electric power source420is predicted to have used more than the available electric energy424.

In that case, the ECU460may recommend a modification to the planned operating profile to ensure that the predicted energy usage does not exceed either the total diesel energy available or the total electric energy available.FIG.12shows an example of such a proposed modification. In particular,FIG.12shows a modified planned operating profile600′ and a modified predicted power expenditure schedule610′ in which the compactor100is operated on full diesel power in the third segment. Curve426′ shows the energy usage of the electric power source420over the course of the modified planned operating profile600′ based on the modified predicted power expenditure schedule610′, while curve428′ shows the energy usage of the internal combustion power source410over the course of the modified planned operating profile600′. As shown in the graph, at the end of the planned operating profile, the internal combustion power source410is predicted to have used less than the available diesel energy422, and the electric power source420is predicted to have used less than the available electric energy424.

It will be appreciated that it is possible in some embodiments for the DC power controller370increase the power output of the diesel power source410to exceed the power demanded by the drive and vibration motors. In that, case the battery/supercap165in the electric power source420can be charged by the power source410during system operation. That is, the motor demand may be covered 100% from diesel power, with additional remaining power being used to charge the electrical power source420.

FIG.13is a block diagram illustrating certain functional units of an ECU260. In particular, an ECU260according to some embodiments includes an equipment control unit1302that controls the operation of functional subsystems of a compactor, including the hybrid power generation subsystem400, the traction power subsystem430, the vibration subsystem440and the electronics power subsystem450. The ECU260further includes a planned operating profile evaluation unit1304that constructs and/or evaluates a planned operating profile for the compactor100. In particular, planned operating profile evaluation unit1304may receive user and/or sensor inputs to construct a planned operating profile of the compactor100. The ECU260further includes a power expenditure schedule generation unit1306that generates a power expenditure schedule for the compactor100based on the planned operating profile. The power expenditure schedule may be calculate the overall energy and power available to complete a task taking into account factors such as the state of charge of an electrical power source, the fuel level of a diesel power source, the ambient temperature, inputs by the operator, and other factors. Based on the power expenditure schedule, the ECU260may generate a modified operating profile that meets one or more planning criteria, such as reducing or minimizing total power usage, reducing CO2emissions, reducing operating time, etc. The ECU260further includes a communication unit1308for communicating proposed changes or other information about a planned operating profile or the predicted power expenditure schedule to an operator.

Operations of an ECU260of a compactor100according to some embodiments are illustrated in the flowchart ofFIG.14. As shown therein, the ECU260obtains a planned operating profile of the compactor100(block902) and generates a predicted power expenditure schedule for the compactor100based on the planned operating profile (block904). The ECU60calculates a total energy expenditure for the planned operating profile (block906), and determines (908), based on the predicted power expenditure schedule, whether a predicted energy expenditure of the compactor100will exceed an available energy of the compactor. If the ECU260determines that the predicted energy expenditure of the compactor will exceed the available energy of the compactor100, the ECU260generates (910) a modified operating profile and operates (912) the compactor100according to the modified operating profile.

The planned operating profile of the compactor may include a predicted movement path and a predicted vibration profile for the compactor.

Generating the modified operating profile may include modifying the predicted movement path or the predicted vibration profile of the compactor.

The planned operating profile of the compactor may include a predicted power expenditure schedule, and generating the modified operating profile may include modifying the predicted power expenditure schedule of the compactor.

The predicted power expenditure schedule of the compactor may specify sources of power for the compactor over a range of operation covered by the planned operating profile of the compactor.

The compactor may include a hybrid power source including an electric power source and an internal combustion engine, and the power source profile may specify a first percentage of power supplied by the electric power source and a second percentage of power supplied by the internal combustion engine over a time period covered by the power source profile.

The planned operating profile of the compactor may include a predicted power expenditure schedule that specifies how power generated by the compactor is allocated among a plurality of operating subsystems of the compactor, and generating the modified operating profile may include modifying the predicted power expenditure schedule of the compactor.

The plurality of operating subsystems of the compactor include a traction power subsystem, a vibration subsystem and an electronics power subsystem.

Generating the modified operating profile may include reducing a power budget of one of the plurality of operating subsystems of the compactor.

The electronic control unit may, in response to determining that the predicted energy expenditure of the compactor exceeds the available energy of the compactor, display an informational message to an operator of the compactor.

The predicted power expenditure schedule may be based on a fuel level of the compactor, ambient temperature, compaction speed, vibration frequency, vibration amplitude, maximum compaction time, compaction distance, width of compaction track, compaction substrate type, compaction substrate temperature, and/or compaction substrate thickness.

In some embodiments, the predicted power expenditure schedule may be based on a state of charge of the supercapacitor or the chemical battery.

According to some embodiments, a control system for a compactor100according to some embodiments includes a compaction range and compaction path estimator that uses sensor data to calculate the overall energy and power available to complete a task taking into account factors such as the state of charge of an electrical power source, the fuel level of a diesel power source, the ambient temperature, inputs by the operator, and other factors and responsively generates a proposed operating plan with path routing, energy balance calculation, and optimization of hybrid and full electric modes to ensure adequate power is available for the paving operation while reducing emissions and also providing the operator feedback regarding proposed corrections to the plan if the power demand cannot be met by the system.

Although embodiments of the inventive concepts have been described herein in the context of an autonomous single roller surface compactor, it will be appreciated that the inventive concepts described herein can be applied and/or implemented in many different types of surface compactors and other construction vehicles. For example, the power/energy management systems/methods may be advantageously employed in construction vehicles such as pavers, haulers, excavators, loaders, pipe layers, etc.

FURTHER DEFINITIONS AND EMBODIMENTS

As will be appreciated by one skilled in the art, aspects of the present disclosure may be illustrated and described herein in any of a number of patentable classes or context including any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof. Accordingly, aspects of the present disclosure may be implemented entirely hardware, entirely software (including firmware, resident software, micro-code, etc.) or combining software and hardware implementation that may all generally be referred to herein as a “circuit,” “module,” “component,” or “system.” Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable media having computer readable program code embodied thereon.

Any combination of one or more computer readable media may be utilized. The computer readable media may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an appropriate optical fiber with a repeater, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computer readable signal medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatuses (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable instruction execution apparatus, create a mechanism for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable medium that when executed can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions when stored in the computer readable medium produce an article of manufacture including instructions which when executed, cause a computer to implement the function/act specified in the flowchart and/or block diagram block or blocks. The computer program instructions may also be loaded onto a computer, other programmable instruction execution apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatuses or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

The foregoing description of the embodiments of the inventive concepts has been presented for the purpose of illustration and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teachings. It is therefore intended that the scope of the inventive concepts be limited not by this detailed description, but rather by the claims appended hereto.