Patent Publication Number: US-11648812-B2

Title: No roll torsion bar

Description:
BACKGROUND 
     Field 
     This disclosure relates to a system, method, apparatus and/or device to improve the ride quality of a ride of a vehicle. 
     Description of the Related Art 
     Torsion bar suspensions are used on modern vehicles, such as trucks and sport utility vehicles (SUVs). The torsion bar suspensions allow for a soft ride due to their elasticity, durability, adjustability of the ride height and small profile along the width of the vehicle. A torsion bar suspension uses a torsion bar as its main weight-bearing spring. One end is attached to the vehicle chassis and the opposite end terminates in a level, such as a torsion key, mounted perpendicular to the bar, that is attached to a suspension arm, a spindle or the axle of the vehicle. While the ride height may be adjusted by turning adjuster bolts on the torsion key, rotating the torsion key too far can bend the adjuster bolts place the shock piston outside its standard travel. Over-rotating the torsion bars can also cause the suspension to hit the bump-stop prematurely, causing a harsh ride. 
     Typically, torsion bar suspensions have a torsion bar adjuster that allows a person to loosen or tighten the torsion bar, which allows for fixed height adjustment of the ride height where the ride height remains fixed until a user re-adjusts the torsion bar to adjust the pre-load that manages the ride height, e.g., by bolting or unbolting the torsion bar. The pre-load, however, remains fixed during the entire ride and until the user manually re-adjusts the torsion bar via the torsion bar adjuster. 
     Accordingly, there is a need for a system, apparatus and/or method to control the load on the torsion bar to adjust a ride height on-the-fly and/or during use of the vehicle. 
     SUMMARY 
     In general, one aspect of the subject matter described in this disclosure may be embodied in an active torsion bar system (“torsion bar system”). The torsion bar system includes a first torsion bar. The first torsion bar is configured to adjust a ride height of a first wheel of a vehicle. The torsion bar system includes a first actuator. The first actuator is coupled to the first torsion bar. The first actuator is configured to control a load on the first torsion bar. The torsion bar system includes an electronic control unit. The electronic control unit is coupled to the first actuator. The electronic control unit is configured to set a position of the first torsion bar using the first actuator and based on the load on the first torsion bar. 
     These and other embodiments may optionally include one or more of the following features. In order to set the position of the first torsion bar, the electronic control unit is configured to cause the first actuator to wind the first torsion bar to increase the ride height of the first wheel or cause the first actuator to unwind the first torsion bar to decrease the ride height of the first wheel. 
     The torsion bar system may include a sensor. The sensor may be configured to detect sensor data. The electronic control unit may be configured to determine the load on the first torsion bar based on the sensor data. The sensor may be a camera. The camera may be positioned on a front of the vehicle or a rear of the vehicle. The sensor may be configured to capture image data. The electronic control unit may be configured to recognize an object or a change in a path in the image data. The electronic control unit may be configured to set the position of the first torsion bar before the vehicle traverses the object or the path. 
     The torsion bar system may include a second torsion bar. The second torsion bar may be configured to adjust a second ride height of a second wheel of the vehicle. The torsion bar system may include a second actuator. The second actuator may be coupled to the second torsion bar. The electronic control unit may be coupled to the second actuator and may be configured to set a position of the second torsion bar using the second actuator and may be based on the load on the second torsion bar. The electronic control unit may be configured to set the position of the second torsion bar independently of the position of the first torsion bar. 
     The electronic control unit may be configured to cause the first actuator to wind the first torsion bar to increase the ride height when the driving mode is the sport mode. The electronic control unit may be configured to cause the first actuator to unwind the first torsion bar to decrease the ride height when the driving mode is the luxury mode. The torsion bar system may include a height sensor on each wheel of the vehicle. The height sensor may be configured to measure a height of each wheel of the vehicle. The electronic control unit may be configured to determine a roll of the vehicle based on the height of each wheel. The electronic control unit may be configured to set the position of the first torsion bar based on the roll of the vehicle. 
     The torsion bar system may include a yaw sensor. The yaw sensor may include an accelerometer or gyroscope. The yaw sensor may be configured to measure an angular velocity of the vehicle around a vertical axis. The torsion bar system includes a pitch sensor. The pitch sensor may be configured to measure a pitch about a lateral axis of the vehicle. The electronic control unit may be configured to set the position of the first torsion bar based on the angular velocity or the pitch of the vehicle. 
     In another aspect, the subject matter may be embodied in a torsion bar system. The torsion bar system includes a first torsion bar. The first torsion bar is configured to adjust a ride height of a first wheel of a vehicle. The torsion bar system includes a first actuator. The first actuator is coupled to the first torsion bar and is configured to apply a first torque to wind or unwind the first torsion bar. The torsion bar system includes an electronic control unit. The electronic control unit is coupled to the first actuator and configured to set a position of the first torsion bar using the first actuator. 
     In another aspect, the subject matter may be embodied in a method for adjusting a ride height of a vehicle. The method includes obtaining, by a processor, sensor data. The method includes determining, by the processor, a load or an amount of torque to apply to a torsion bar of the vehicle based on the sensor data. The method includes winding or unwinding the first torsion bar based on the load or the amount of torque to apply to decrease or increase the ride height. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other systems, methods, features, and advantages of the present invention will be apparent to one skilled in the art upon examination of the following figures and detailed description. Component parts shown in the drawings are not necessarily to scale and may be exaggerated to better illustrate the important features of the present invention. 
         FIG.  1    shows a block diagram of an example active torsion bar system according to an aspect of the invention. 
         FIG.  2    shows a diagram of the interconnection of various components of the active torsion bar system of  FIG.  1    according to an aspect of the invention. 
         FIG.  3    is a flow diagram of an example process for setting the load or pre-load of the one or more torsion bars using the active torsion bar system of  FIG.  1    according to an aspect of the invention. 
         FIG.  4    is a flow diagram of an example process adjusting the load or pre-load of the one or more torsion bars using the active torsion bar system of  FIG.  1    according to an aspect of the invention. 
         FIG.  5    is a diagram of various angles and/or orientations of the vehicle that are measured using the active torsion bar system of  FIG.  1    to adjust the ride height of the wheels of the vehicle according to an aspect of the invention. 
         FIG.  6    shows an example use-case of the vehicle travelling off-road using the active torsion bar system of  FIG.  1    according to an aspect of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are systems, apparatuses, and methods for an active torsion bar suspension system (or “torsion bar system”) that actively controls, manages or adjusts a load or pre-load on the torsion bar. The torsion bar system may control, manage or adjust the load or the pre-load on the torsion bar automatically, on-the-fly and/or in real-time. By controlling, managing or adjusting the load or the pre-load on the torsion bar, the torsion bar system may wind or unwind the tension within the torsion bar on-the-fly, which increases or decreases resistance to adjust the ride height of the vehicle. The resistance of the torsion bar to the twisting has the same effect as a spring used in more conventional suspension systems and a certain amount of the load is applied to the torsion bar, which causes the ride to be softer or harder due to the load. This improves the comfort of the driver and passengers during the ride. For example, as the vehicle traverses over a speed bump or other obstacle, the torsion bar system may increase the tension or wind the torsion bar to increase the ride height, which softens the overall ride as the vehicle traverses over the speed bump or other obstacle. 
     Other benefits and advantages include the capability to monitor various parameters of the ride and automatically adjust the torsion bar on-the-fly and in response to the monitored parameters. For example, the torsion bar system may detect a change in one or more parameters, such as the yaw, roll or pitch of the vehicle, and adjust the torsion bar to adjust the ride height of a wheel, accordingly. This allows the torsion bar system to automatically adjust the ride height, and consequently, the comfort of the occupants of the vehicle automatically during the ride. 
     Additionally, the torsion bar system may control each torsion bar that is coupled to different wheels independently. For example, the torsion bar system may raise or lower the ride height of the front passenger-side wheel while simultaneously raising or lowering the ride height of the rear driver-side wheel independently. This further enhances the comfort of the occupants of the vehicle as the ride heights of each wheel of the vehicle is independently adjustable to be responsive to surface features or objects that are driven over by each wheel. 
       FIG.  1    is a block diagram of an active torsion bar suspension system (or “torsion bar system”)  100 . The torsion bar system  100  or a portion thereof may be retro-fitted, coupled to, include or be included within a vehicle  102  or separate from the vehicle  102 . The torsion bar system  100  may adjust or control one or more torsion bars  112  of the vehicle  102  to adjust the ride height of one or more wheels  114  of the vehicle  102 . By adjusting the ride height of the one or more wheels  114  of the vehicle  102 , the torsion bar system  100  adjusts the “ride” or ride quality of the vehicle&#39;s effectiveness in insulating the occupants from undulations in the road surface (e.g., bumps or corrugations). A vehicle  102  with good ride quality provides comfort to the driver, passenger and other occupants of the vehicle  102 . 
     The torsion bar system  100  may have or use a network  106  to communicate among different components, such as among the vehicle  102  and/or a personal device  104 . The personal device  104  may be used as a user interface to control, adjust or set a position of one or more torsion bars  112  of the vehicle  102  to adjust the ride heights of the different wheels  114  of the vehicle  102 . The personal device may be, for example, a personal computer, a laptop, a tablet, a smartphone or other personal or wearable smart device. The network  106  may be a Dedicated Short-Range Communication (DSRC) network, a local area network (LAN), a wide area network (WAN), a cellular network, the Internet, or combination thereof, that connects, couples and/or otherwise communicates among the different components of the torsion bar system  100 . 
     The torsion bar system  100  may include, be included within or be retro-fitted to the vehicle  102 . A vehicle  102  is a conveyance capable of transporting a person, an object, or a permanently or temporarily affixed apparatus. The vehicle  102  may be a self-propelled wheeled conveyance, such as a car, a sports utility vehicle, a truck, a bus, a van or other motor, battery or fuel cell driven vehicle. For example, the vehicle  102  may be an electric vehicle, a hybrid vehicle, a hydrogen fuel cell vehicle, a plug-in hybrid vehicle or any other type of vehicle that has a fuel cell stack, a motor and/or a generator. Other examples of vehicles include bicycles, trains, planes, or boats, and any other form of conveyance that is capable of transportation. The vehicle  102  may be semi-autonomous or autonomous. That is, the vehicle  102  may be self-maneuvering and navigate without human input. An autonomous vehicle may have and use one or more sensors and/or a navigation unit to drive autonomously. 
     The vehicle  102  may have one or more wheels  114 , which are used to move the vehicle  102 . The torsion bar system  100  may include one or more torsion bars  112 . A torsion bar  112  may be a metal bar that acts as a weight-bearing spring. When there is a vertical motion on the wheel, the torsion bar  112  may twist around its axis and is resisted by the bar&#39;s torsion resistance. The effective spring rate of the torsion bar may be determined by its length, cross section, shape, material and manufacturing process. The one or more torsion bars  112  may each be coupled to a corresponding wheel of the one or more wheels  114 . Each of the one or more torsion bars  112  may be independent of the other torsion bars  112  to allow for independent control and/or adjustment of the ride height of the corresponding wheel of the one or more wheels  114 , as shown in  FIG.  2    for example. That is, the torsion bar system  100  may independently control or set a position for each of the one or more torsion bars  112 , e.g., using one or more actuators  120  which independently control the ride height of the corresponding wheel  114  so that the torsion bar system  100  may raise or lower the ride height of one wheel without affecting the control of the ride height of another wheel. The torsion bar system  100  may control each torsion bar  112  independently without a sway bar or other coupling component. By removing the sway bar, the wheel articulation, which may be measured by a ramp travel index (RTI), is improved, e.g., the difference between the ride heights of the passenger and driver-side wheels is not limited. Moreover, by removing the sway, bar or other coupling component between two or more torsion bars  112 , the overall costs and weight of the torsion bar system  100  are reduced. 
     The torsion bar system may have one or more actuators  120 . The one or more actuators  120  may be coupled to the one or more torsion bars  112 . The one or more actuators  120  may be a device that receives a control signal and a source of energy to twist or wind, e.g., to apply more torque, the torsion bar  112 , or untwist or unwind, e.g., to release the torque, the torsion bar  112  to adjust the ride height of the one or more wheels  114 . 
     Each actuator  120  of the one or more actuators  120  may be coupled to a corresponding torsion bar  112  that controls the ride height of a corresponding wheel  114  of the vehicle  102 . Each of the one or more actuators  120  may be independent of the other actuators of the one or more actuators  120 . 
     The torsion bar system  100  includes one or more processors, such as the electronic control unit (ECU)  108 . The one or more processors, such as the ECU  108 , may be implemented as a single processor or as multiple processors. For example, the one or more processors may be a microprocessor, data processor, microcontroller or other controller, and may be electrically coupled to some or all the other components within the vehicle  102 . The one or more processors may obtain sensor data from one or more sensors  116  and/or user input from the user interface  118  to be used to adjust the ride height of the wheels  114  of the vehicle  102 . The one or more processors may control one or more actuators  120  to set the position of the one or more torsion bars  112  to control the ride height of the wheels  114  of the vehicle  102 . 
     The memory  110  may be coupled to the ECU  108 . The memory  110  may include one or more of a Random Access Memory (RAM), Read Only Memory (ROM) or other volatile or non-volatile memory. The memory  110  may be a non-transitory memory or a data storage device, such as a hard disk drive, a solid-state disk drive, a hybrid disk drive, or other appropriate data storage, and may further store machine-readable instructions, which may be loaded and executed by the ECU  108 . The memory  110  may store one or more configuration settings or mappings that associate different values of the sensor data and/or the user input to a corresponding load or pre-load on the one or more torsion bars  112 , which affects the ride height of the one or more wheels  114 . 
     The torsion bar system  100  may include a user interface  118 . The user interface  118  may include an input device that receives user input from a user interface element, a button, a dial, a microphone, a keyboard, or a touch screen. For example, the touch screen may include a graphical user interface or menu for a drive mode selector. The drive mode selector may have various modes including but not limited to a luxury mode, a normal mode, an economy mode and/or a sport mode. Each of the different modes may be associated with a different level of ride quality, e.g., more or less body roll, that is desired by the occupants of the vehicle when traversing across an undulation in the road surface, which may affect the load or pre-load applied to each of the one or more torsion bars  112 . 
     The user input may include one or more configuration settings. The one or more configuration settings may indicate a default or a pre-ride amount of load or pre-load to apply to each of the one or more torsion bars  112  before a road trip begins. The user input may indicate one or more thresholds, such as a height of the wheel or the pitch or yaw of the vehicle  102 , which may trigger an adjustment of the position of one or more torsion bars  112  to adjust the ride height of the one or more wheels  114 . 
     The user interface  118  may include, provide or be coupled to an output device, such as a display or other visual indicator. The user interface  118  may provide notifications, warnings or alerts, for example. The user interface  118  may provide additional information including the ride height of the one or more wheels  114  or the sensor data. 
     The torsion bar system  100  may include a network access device  122 . The network access device  122  may include a communication port or channel, such as one or more of a Dedicated Short-Range Communication (DSRC) unit, a Wi-Fi unit, a Bluetooth® unit, a radio frequency identification (RFID) tag or reader, or a cellular network unit for accessing a cellular network (such as 3G, 4G or 5G). The network access device  122  may transmit data to and receive data from the different components the torsion bar system  100 , such as the vehicle  102  and/or the personal device  104 . 
     The torsion bar system  100  may include one or more sensors  116 . The one or more sensors  116  may include a camera  116   a . The camera  116   a  may be positioned on a front and/or a rear of the vehicle  102 . The camera  116   a  may be positioned on the front of the vehicle  102  and may record and/or capture image data of the path in front of the vehicle  102  as the vehicle  102  is moving forward. The image data may include one or more undulations in the road or surface that may be in the path of the vehicle  102  as the vehicle  102  is moving forward. The camera  116   a  may be positioned on the rear of the vehicle  102  and may record and/or capture image data of the path behind the vehicle  102  as the vehicle  102  is moving in reverse. The image data may include one or more undulations in the road or surface that may be in the path of the vehicle  102  as the vehicle  102  is moving in reverse. 
     The one or more sensors  116  may measure various angles and/or orientations of the vehicle  102  about various axes, which may affect the ride quality of the ride. The various angles and/or orientations of the vehicle  102  may include the roll  502 , the pitch  504  and/or the yaw  506 , as shown in  FIG.  5    for example. 
     The one or more sensors  116  may include one or more height sensors  116   b . The one or more height sensors  116   b  may be positioned near or in proximity to a corresponding wheel  114  of the vehicle  102 . The height sensor  116   b  may measure a height of the corresponding wheel  114  relative to the surface of the road or other surface. The torsion bar system  100  may measure the height of each wheel of the vehicle  102  and determine the roll  502  of the vehicle  102  based on the height of each wheel. The roll  502  of the vehicle  102  defines the distribution of the weight of the vehicle  102  while the vehicle  102  is turning, e.g., the clockwise and/or counter-clockwise movement of the vehicle  102  about an axis  508  through the front of the vehicle  102 . By determining the roll  502  of the vehicle  102 , the torsion bar system  100  may adjust the ride height of one or more wheels  114  in response to the roll  502  of the vehicle  102  to balance the vehicle  102  when at least one height of one wheel is disproportionately higher or lower than the other wheels of the vehicle  102 . 
     The one or more sensors  116  may include a pitch sensor  116   c . The pitch sensor  116   c  may be configured to measure the pitch  504  of the vehicle  102  about a lateral axis  510  of the vehicle  102 . The pitch  504  of the vehicle  102  is a measure of the height in the vehicle&#39;s weight forwards or backwards, which may cause the front end of the vehicle  102  to drop or lift and the rear end of the vehicle  102  to lift or drop, respectively. The one or more sensors  116  may include a yaw sensor  116   d . The yaw sensor may be an accelerometer and/or a gyroscopic device that measures a vehicle&#39;s yaw  506  or yaw rate, or angular velocity around its vertical axis  512 . 
     The torsion bar system  100  may be coupled to one or more vehicle components of the vehicle  102 . The one or more vehicle components may include a navigation unit  124 . The navigation unit  124  may be integral to the vehicle  102  or a separate unit. The vehicle  102  may include a Global Positioning System (GPS) unit (not shown) for detecting location data including a current location of the vehicle  102  and date/time information instead of the navigation unit  124 . In some implementations, the ECU  108  may perform the functions of the navigation unit  124  based on data received from the GPS unit. The navigation unit  124  or the ECU  108  may perform navigation functions. Navigation functions may include, for example, route and route set prediction, providing navigation instructions, and receiving user input such as verification of predicted routes and route sets or destinations. The navigation unit  124  may be used to obtain navigational map information. The navigational map information may include a starting location of the vehicle  102 , a current location of the vehicle  102 , a destination location, a route between the starting location of the vehicle  102  and the destination location and/or date/time information. 
     The one or more vehicle components may include a motor and/or generator  128 . The motor and/or generator  128  may convert electrical energy into mechanical power, such as torque, and may convert mechanical power into electrical energy. The motor and/or generator  128  may be coupled to the battery  126 . The motor and/or generator  128  may convert the energy from the battery  126  into mechanical power, and may provide energy back to the battery  126 , for example, via regenerative braking. The one or more vehicle components may include one or more additional power generation devices, such as an engine  130  or a fuel cell stack (not shown). The engine  130  combusts fuel to provide power instead of and/or in addition to the power supplied by the motor and/or generator  128 . 
     The battery  126  may be coupled to the motor and/or generator  128  and may supply electrical energy to and receive electrical energy from the motor and/or generator  128 . The battery  126  may include one or more rechargeable batteries and may supply the power to the torsion bar system  100 . 
     The battery management control unit (BMCU)  132  may be coupled to the battery  126  and may control and manage the charging and discharging of the battery  126 . The BMCU  132 , for example, may measure, using battery sensors, parameters used to determine the state of charge (SOC) of the battery  126 . The BMCU  132  may control the battery  126 . 
     The one or more vehicle components may include a transmission  134 . The transmission may have one or more gears, a drivetrain, a clutch and/or a drive shaft. The transmission  134  converts the power from the engine  130  to move the wheels  114  of the vehicle  102 . 
       FIG.  2    shows the interconnection of various components of the torsion bar system  100 . The torsion bar system  100  may have an electronic control unit  108 , one or more torsion bars  112 , one or more actuators  120  and one or more wheels  114 . The electronic control unit  108  may independently control each of the one or more actuators  120 , such as the actuators  120   a - d . And since each of the torsion bars  112   a - d  are independent of each other, the electronic control unit  108  may control each actuator  120   a - d  to adjust the position of each torsion bar  112   a - d  independently. The electronic control unit  108  may twist or wind the corresponding torsion bar  112   a - d  to apply a torque to or set a position of the corresponding torsion bar  112   a - d  that sets the load or the pre-load of the corresponding torsion bar  112   a - d . For example, the electronic control unit  108  may cause the actuator  120   a  to wind the torsion bar  112   a  a first amount, cause the actuator  120   b  to wind the torsion bar  112   b  a second amount, cause the actuator  120   c  to unwind the torsion bar  112   c  a third amount and/or cause the actuator  120   d  to unwind the torsion bar  112   d  a fourth amount. The first, second, third and fourth amounts may be the same and/or different. This allows the ride height of each wheel  114   a - d  to each be individually adjusted independently of the adjustments to the ride heights of the other wheels  114   a - d.    
     For example, when the vehicle  102  is approaching an undulation, a pothole or other obstacle in the road surface that may be traversed only by the passenger-side wheels  114   c - d , the electronic control unit  108  may only need to adjust the ride heights of the wheels  114   c - d , e.g., by adjusting the position of the torsion bars  112   c - d . In another example, when the vehicle  102  is pitched upward, such as when there is a heavy load on the rear of the vehicle  102 , which causes the rear of the vehicle  102  to angle downward and the front of the vehicle  102  to angle upward, the electronic control unit  108  may cause actuators  120   b ,  120   d  to untwist or unwind, such as in a counter-clockwise motion, the torsion bars  112   b ,  112   d  to decrease the ride height of the wheels  114   b ,  114   d  and resist the weight and/or cause the actuators  120   a ,  120   c  to twist or wind, such as in a clockwise motion, the torsion bars  112   a ,  112   c  to increase the ride height of the wheels  114   a ,  114   c  to keep the wheels  114   a ,  114   c  on the ground. 
       FIG.  3    is a flow diagram of a process  300  for setting the position of the one or more torsion bars  112 . One or more computers or one or more data processing apparatuses, for example, the ECU  108  of the torsion bar system  100  of  FIG.  1   , appropriately programmed, may implement the process  300 . The torsion bar system  100  may be used to adjust the load or pre-load (hereinafter, referred to as “load”) on the one or more torsion bars  112 . This allows the torsion bar system  100  to adjust the ride height of each wheel  114  on-the-fly and/or automatically throughout a ride even when the vehicle  102  is moving and traversing across the road surface, which improves the ride quality of the ride. The torsion bar system  100  may obtain or determine various parameters of the environment surrounding the vehicle  102 , such as sensor data from one or more sensors  116 , and/or user preferences, such as a driving mode from a drive mode selector, to determine the load on the torsion bar  112  to set the vehicle ride height to provide the desired ride quality. 
     The torsion bar system  100  may obtain one or more user preferences including one or more driving modes that indicate a desired ride quality ( 302 ). The torsion bar system  100  may obtain the driving mode via a user interface  118 , such as a graphical user interface or menu for a drive mode selector. The one or more driving modes may include a luxury mode, an off-road mode, a normal driving mode and/or a sports mode. Each of the one or more driving modes may be associated or mapped to different loads on the one or more torsion bars  112 . 
     For example, when the sport mode is selected, the torsion bar system  100  may adjust the pre-load on each of the one or more torsion bars  112  so the torsion bars  112  are set so that the initial ride height of the wheels  114  are lower than the normal mode, which allows less body roll than the normal mode. In another example, when the luxury mode is selected, the torsion bar system  100  may adjust the pre-load of each of the one or more torsion bars  112  so the torsion bars  112  are set so that the initial ride height of the wheels  114  is higher than the normal mode, which allows for more body roll. This causes the vehicle  102  to have a higher ride height than the normal mode and so undulations or unevenness in the road surface are not felt, as much, by occupants of the vehicle  102  when the vehicle  102  traverses the undulations or unevenness in the road surface. 
     In another example, when the off-road mode is selected, the torsion bar system  100  may adjust the pre-load of each of the one or more torsion bars  112  so the torsion bars  112  are set so that the initial ride height of the wheels  114  is at a maximum, which is higher than when the normal mode or the luxury mode is selected and allows for the most body roll. This causes the wheels  114  to be set to have the maximum clearance above the road surface and allows the vehicle  102  to traverse large obtrusions in the road surface. When the different driving modes are selected, the torsion bar system  100  may also allow for the bound dampening force on the shock absorbers to be adjusted based on the driving modes. 
     The torsion bar system  100  may obtain navigational map information including one or more road features ( 304 ). The torsion bar system  100  may obtain the navigational map information including the one or more road features and their corresponding locations using the navigation unit  124 . The one or more road features may include one or more undulations in the road surface, such as a speed bump. The one or more road features may include other road features, such as potholes or road debris, which may affect the smoothness of the road surface and may cause a vertical deflection that affects the ride quality. 
     The torsion bar system  100  may measure a height of each wheel  114  ( 306 ). The torsion bar system  100  may measure the height of each wheel using a height sensor  116   b . A height sensor  116   b  may be positioned at or near each wheel  114  of the vehicle  102 . Each height sensor  116   b  may detect the ride height of each wheel  114  and provide a signal to the ECU  108  that indicates the individual height of each wheel  114 . The ECU  108  obtains the individual height of each wheel  114  and uses the heights to determine the roll of the vehicle  102 . 
     Once the height of each wheel  114  is obtained, the torsion bar system  100  may determine the roll or roll angle of the vehicle  102  ( 308 ). The torsion bar system  100  may determine the roll or roll angle (hereinafter, “roll”) of the vehicle  102  based on the height of each of the one or more wheels  114 . The roll is the angle of lean from the vertical angle that is caused due to the centripetal force, which acts on the vehicle  102  when negotiating corners during a turn. The roll is the differences between the groundline and the body in the angle of the car that is to be achieved. The torsion bar system  100  may compare the height of each of the one or more wheels  114  on the driver side of the vehicle  102  to the height of each of the one or more wheels  114  on the passenger side of the vehicle  102 . The torsion bar system  100  may calculate a difference between the heights of the wheels  114  on the driver side and the heights of the wheels  114  on the passenger side to determine the roll of the vehicle  102 . 
     The torsion bar system  100  may measure the yaw of the vehicle  102  ( 310 ). The yaw of the vehicle  102  (or the “yaw rotation, rate or velocity”) is a movement around the yaw axis of the vehicle  102  that changes the direction the vehicle  102  is pointing, to the left or right of its direction of motion. The yaw happens when the weight of the vehicle  102  shifts from its center of gravity to the left or the right. The yaw rate or yaw velocity of the vehicle is the angular velocity of this rotation, or rate of change of the heading angle when the vehicle is horizontal. The torsion bar system  100  may use a yaw sensor  116   d , such as a gyroscope or accelerometer, to measure the yaw rotation. The yaw may be measured by measuring the ground velocity at two geometrically separated points within the body or may use a gyroscope or be synthesized from an accelerometer. 
     The torsion bar system  100  may measure a pitch of the vehicle  102  ( 312 ). The torsion bar system  100  may use a pitch sensor to measure the pitch of the vehicle  102 . The pitch of the vehicle  102  is the shift in the weight of the vehicle  102  forwards or backwards. For example, when there is a heavy load on the rear of the vehicle  102  the front of the vehicle  102  pitches or angles upward. In another example, when the vehicle  102  brakes, the front of the vehicle  102  may pitch or angle downward while the rear of the vehicle  102  may pitch or angle upward. When a weight of the vehicle  102  moves forward or backwards—from the back to the front or from the front to the back—one end of the vehicle may drop while the opposite end of the vehicle may lift. 
     The torsion bar system  100  may capture image data of the surrounding environment of the vehicle  102  ( 314 ). The torsion bar system  100  may have a camera  116   a  positioned on the front of the vehicle  102  and/or positioned on the rear of the vehicle  102 . When the vehicle  102  is moving forward, the camera  116   a  positioned in the front of the vehicle  102  may capture image data in front of the vehicle  102 . The image data may include undulations or other road features in the road surface that are in the path of the vehicle  102  when the vehicle  102  is moving forward. When the vehicle  102  is moving in reverse, the camera  116   a  positioned in the rear of the vehicle  102  may capture image data in the rear of the vehicle  102 . The image data may include undulations or other road features in the road surface that are in the path of the vehicle  102  when the vehicle  102  is moving in reverse. 
     Once the sensor data, image data, navigation map information and/or the driving mode are obtained, determined or measured, the torsion bar system  100  determines the load for each of the one or more torsion bars  112  ( 316 ). The torsion bar system  100  may apply different loads for each of the one or more torsion bars  112  and balance the loads for each of the one or more torsion bars  112  to optimize the ride quality of the ride. The torsion bar system  100  may map the sensor data, image data, navigational map information and/or the driving mode to different loads on the one or more torsion bars  112 . 
     Once the load for each of the one or more torsion bars  112  is determined, the torsion bar system  100  sets the position of each of the one or more torsion bars  112  ( 318 ). The torsion bar system  100  sets the position of each torsion bar  112  based on the determined load for each torsion bar  112 . The ECU  108  may cause each actuator  120  for each torsion bar  112  to twist or wind to apply torque to the corresponding torsion bar  112 , which causes the ride height of the corresponding wheel  114  to increase and/or to untwist or unwind to release torque of the corresponding torsion bar  112 , which causes the ride height of the corresponding wheel  114  to decrease. Since the torsion bar system  100  sets the position of each of the one or more torsion bars  112 , independently, of the other torsion bars  112 , the torsion bar system  100  controls the ride height of each wheel  114  independently. 
     In some implementations, the one or more actuators  120  may apply or release the torque upon receiving a control signal from the electronic control unit  108 . The rate that the torque is applied or released may be based on the rate of change in the sensor data that is measured or determined. As the magnitude of the change in the sensor data increases, the rate of change of the torque that is applied or released may be increased. And as the magnitude of the change in the sensor data decreases, the rate of change of the torque may be decreased. The rate may be limited by a threshold safety margin to prevent damage to the components of the torsion bar system  100 . 
       FIG.  4    is a flow diagram of a process  400  for setting the load or pre-load of the one or more torsion bars  112 . One or more computers or one or more data processing apparatuses, for example, the ECU  108  of the torsion bar system  100  of  FIG.  1   , appropriately programmed, may implement the process  400 . 
     The torsion bar system  100  obtains the navigational map information, the image data, sensor data and/or the driving mode, as described above ( 402 ). Once the navigational map information, the image data, sensor data and/or the driving mode are obtained, measured or determined, the torsion bar system  100  may determines the pre-load for each of the one or more torsion bars  112  based on the driving mode ( 404 ). The torsion bar system  100  may set or determine the initial or baseline pre-load based on the driving mode, and may reconfigure the initial or baseline pre-load while driving if the torsion bar system  100  receives user input indicating a change in the driving mode from one driving mode to another or other information. The different driving modes may include a luxury mode, a normal mode, a sports mode and an off-road mode. 
     The normal mode may be the default driving mode where the torsion bar system  100  is balanced and applies a torque of approximately 45%-55% of the maximum applied torque to each of the one or more torsion bars  112  so that the vehicle  102  is balanced and the ride heights for each of the one or more wheels  114  is substantially equivalent. This may be the default ride height and allow the vehicle  102  to remain planar to a flat road surface with no incline or angle and provides for a ride quality that is smooth yet responsive to deformations in the road surface. 
     When the driving mode is the luxury mode, the torsion bar system  100  may apply approximately 55%-65% of the maximum applied torque for each of the one or more torsion bars  112 . This increases the ride height in comparison to the normal mode and the sports mode, which allows undulations, potholes or other deformations in the road surface to be absorbed. Whereas, when the driving mode is the sport mode, the torsion bar system  100  may apply approximately 35%-45% of the maximum applied torque for each of the one or more torsion bars  112 . This decreases the ride height in comparison to the normal mode, and so, the vehicle  102  rides lower to the road surface. In another example, when the driving mode is the off-road mode, the torsion bar system  100  may apply 75%-85% of the maximum applied torque for each of the one or more torsion bars  112 . This significantly increases the ride height in comparison to all the other driving modes so that the vehicle  102  may traverse undulations or other deformation in the road surface. 
     For example, as shown in  FIG.  6   , the vehicle  102  may be travelling off-road over a rocky terrain  602 , and so, an occupant may use the user interface  118  to select or set the driving mode to the off-road mode. In some implementations, the torsion bar system  100  may identify the one or more undulations or changes in the road surface and automatically switch the driving mode to one of the driving modes. For example, the torsion bar system  100  may identify the rocky terrain  602  and switch the driving mode to the off-road mode or identify other road features, such as a windy road, curve or turn, and switch the driving mode to a corresponding driving mode, such as a sport or luxury mode. By switching the driving mode to the off-road mode, the torsion bar system  100  may wind the one or more torsion bars  112  to increase the ride height  604  of the wheels  114  of the vehicle  102 , which allows the vehicle  102  to traverse the rocky terrain  602  and provides a more comfortable ride to any occupants. 
     Once the initial or baseline pre-load is set, the torsion bar system  100  may determine or identify one or more road features ( 406 ). The torsion bar system  100  may extract the locations of the road features, such as potholes, speed bumps, or other undulations or deformations in the road surface from the navigational map information or recognize the road features from the image data. For example, the torsion bar system  100  may identify the rock  606 . 
     The one or more road features may be an undulation or other deformation in the road surface and/or may be a change in the direction or incline of the road surface, such as a turn, a curve or an angled embankment. In some implementations, the torsion bar system  100  may identify an approaching road feature from user input, such as from an activation of a turn signal, which may indicate that a turn is approaching. 
     The one or more road features may cause one of the wheels  114  to behave differently than the other wheels. The torsion bar system  100  may recognize the type of road feature, e.g., whether the road feature is a speed bump, a pothole, a turn or other change in the road surface. The torsion bar system  100  may recognize the type by comparing the road feature to a database of objects to recognize the type of object and/or may extract a tag from the navigational map information that identifies the type of road feature. In some implementations, the user input indicates the type of road feature, such as right-hand turn or a left-hand turn when a turn signal is activated. 
     Once the torsion bar system  100  identifies or determines that there is a road feature, the torsion bar system  100  may adjust the pre-load when the location of the road feature is within a threshold distance of the current location of the vehicle  102  ( 408 ). When the road feature is within the threshold distance, the torsion bar system  100  adjusts the pre-load in response to determining that the location of the road feature is within the threshold distance to prepare the vehicle  102  to traverse the road feature. The torsion bar system  100  may compare the location of the vehicle  102 , which may be obtained from the navigational map information, to the location of the road feature and when the location of the vehicle  102  is within a threshold distance of the location of the road feature perform the adjustment. 
     The torsion bar system  100  may determine the adjustment of the pre-load of each of the one or more torsion bars  112  based on the type and/or location of the road feature. For example, when the road feature is a pothole, the torsion bar system  100  may recognize that only the passenger-side wheels  114   a - b  may traverse the pothole and only adjust the torsion bars  112   a - b  that control the passenger-side wheels  114   a - b . Thus, the torsion bar system  100  may only adjust the pre-load on the torsion bars  112  that need adjustment. 
     In another example, when the road feature is a turn or curve, the torsion bar system  100  may twist or wind the wheels  114  that are on the outside of the turn or curve to raise or increase the ride height of the outside wheels to prevent the outside wheels from rolling or rising and/or may untwist or unwind the wheels  114  that are on the inside of the turn or curve to lower or decrease the ride height of the inside wheels so that the wheels  114  remain in contact with the road surface during the turn or curve. This decreases the likelihood that the vehicle  102  will roll over. In another example, the torsion bar system  100  may recognize the rock  606  and that the passenger-side wheels will traverse the rock  606 , and so, the torsion bar system  100  may only adjust the passenger-side wheels, e.g., by increasing the ride height, since the passenger-side wheels  114   a - b  traverse the rock  606 . 
     After the torsion bar system  100  determines the pre-load for each of the one or more torsion bars  112 , the torsion bar system  100  sets the position of the one or more torsion bars  112  based on the pre-load for each of the one or more torsion bars  112  ( 410 ). The torsion bar system  100  controls the one or more actuators  120  to wind or unwind the corresponding torsion bar  112  that is coupled to the actuator  120 , as described above. By determining and identifying road features, the torsion bar system  100  predicts when the one or more torsion bars  112  may need to be adjusted to maintain the ride quality. Then, the torsion bar system  100  determines the pre-load for each of the one or more torsion bars  112  that are affected so that the ride quality is maintained before, during and after traversal of the road feature. Since the torsion bar system  100  determines the pre-load before the vehicle  102  traverses the road feature, the torsion bar system  100  is able to set the pre-load before the vehicle  102  traverses the road feature so the torsion bar system  100  may be predictive of the changes necessary instead of reactive. 
     The torsion bar system  100  may obtain one or more thresholds for the sensor data ( 412 ). Each type of sensor data may have a different threshold or range that is acceptable before the torsion bar system  100  adjusts the pre-load. The one or more thresholds may be obtained from the memory  110  and/or obtained via user input via the user interface  118 . In some implementations, the one or more thresholds are pre-programmed and/or pre-configured into the memory  110 . The one or more thresholds may also be based on the driving mode. For example, the one or more thresholds for the sensor data may be different for each of the one or more driving modes, and when selected, each of the one or more driving modes may map to different thresholds for the various types of sensor data. 
     The torsion bar system  100  may determine whether the sensor data exceeds a corresponding threshold ( 414 ). The torsion bar system  100  compares the sensor data to the corresponding threshold to determine whether the torsion bar system  100  needs to re-determine and re-adjust the pre-load for each of the one or more torsion bars  112 . The sensor data may include the yaw, roll and/or pitch. The torsion bar system  100  may compare the yaw, roll and/or pitch that is determined, measured or otherwise obtained, as described above, with one or more corresponding thresholds. And, when the yaw, roll and/or pitch exceeds the one or more corresponding thresholds, this may indicate that the vehicle  102  may need to re-adjust the pre-load on one or more of the torsion bars  112  to adjust the ride height of a corresponding wheel. When the sensor data does not exceed the corresponding threshold, the torsion bar system  100  continues to monitor the sensor data while the vehicle  102  is traversing the road surface ( 402 ). The torsion bar system  100  maintains the position of the one or more torsion bars  112  while the sensor data is within the corresponding thresholds unless one or more of the other factors change, such as the sensor data or the driving mode and/or in response to a road feature. 
     When the sensor data exceeds the corresponding threshold, the torsion bar system  100  re-determines the pre-load and/or adjusts the pre-load on each of the one or more torsion bars  112  ( 416 ). The torsion bar system  100  re-determines the pre-load and/or adjusts the pre-load based on the sensor data. The torsion bar system  100  may re-determine and/or adjust the pre-load based on the difference between the measured or determined sensor data and their corresponding threshold. For example, as the difference is greater, the torsion bar system  100  may need to adjust the pre-load more than when the difference is less to maintain the ride quality of the wheel. By adjusting the pre-load on each of the one or more torsion bars  112  using the sensor data, the torsion bar system  100  reacts to changes to the position of the vehicle  102 , such as when the vehicle  102  rolls, is pitched or otherwise is changing in orientation. When there are changes to the position of the vehicle  102 , the torsion bar system  100  adjusts the position of the one or more torsion bars  112  to adjust the ride height of the wheels  114  of the vehicle  102  so that the vehicle  102  becomes more balanced to improve the ride quality. 
     The torsion bar system  100  re-adjusts or sets the position of the one or more torsion bars  112  based on the pre-load ( 418 ). The torsion bar system  100  uses the one or more actuators to set the position of the one or more torsion bars  112 , as described above, based on the readjusted pre-load to react to changes in the position of the vehicle  102 . 
     Exemplary embodiments of the invention have been disclosed in an illustrative style. Accordingly, the terminology employed throughout should be read in a non-limiting manner. Although minor modifications to the teachings herein will occur to those well versed in the art, it shall be understood that what is intended to be circumscribed within the scope of the patent warranted hereon are all such embodiments that reasonably fall within the scope of the advancement to the art hereby contributed, and that that scope shall not be restricted, except in light of the appended claims and their equivalents.