Patent Description:
There is known a load reduction device that performs assistance of a load such as a walking motion of a user by being worn by the user and mitigates the load of luggage carried by the user. When wearable by a person, the load reduction device is sometimes called a powered suit.

Some powered suits assist walking movement by driving a link mechanism provided on the user's legs by outputting torque from an actuator to assist muscle strength. Patent Document <NUM> discloses a technique of calculating the torque value for driving an actuator based on the joint angle. Patent Document <NUM> relates to a walking support device and a walking support program.

In a load reduction device such as a powered suit, it is necessary to sequentially change the torque required for load reduction according to the momentum of the user's motion. As such, in a load reduction device, it is desired to perform more appropriate load reduction for motions of a user.

Therefore, an example object of the present invention is to provide a load reduction device, a load reduction method, and a storage medium storing a program, which can solve the above-mentioned problem.

The problems are solved according to the features of the independent claims.

The present invention can provide a load reduction device capable of more appropriate load reduction for a user's motion.

Hereinbelow, a load reduction device, a load reduction method, and a storage medium storing a program according to an embodiment of the present invention will be described with reference to the drawings.

<FIG> is a diagram showing a configuration of a powered suit according to the present embodiment.

A powered suit <NUM> is an aspect of the load reduction device. The powered suit <NUM> is constituted by a skeleton portion <NUM>, a belt <NUM>, a hip actuator <NUM>, a knee actuator <NUM>, an ankle actuator <NUM>, a shoe sole plate <NUM>, a foot harness <NUM>, a shoe sole load sensor <NUM> (first measuring unit), a foot sole load sensor <NUM> (second measuring unit), a loading platform <NUM>, a control device <NUM>, a battery <NUM>, a hip joint sensor <NUM>, a knee joint sensor <NUM>, an ankle joint sensor <NUM>, and the like. The skeleton portion <NUM> is roughly classified into a first skeleton portion <NUM>, a second skeleton portion <NUM>, and a third skeleton portion <NUM> as an example.

As shown in <FIG>, the powered suit <NUM> is in one example configured as follows so as to support the loading platform <NUM>, which is one aspect of a mechanism for holding luggage. That is, the powered suit <NUM> is provided with the first skeleton portion <NUM>, and at the left and right hip actuators <NUM> are coupled rotatable to the first skeleton portion <NUM> and the second skeleton portion <NUM>, which corresponds to the left or right thigh portion of the user wearing the powered suit <NUM>, respectively. The left and right knee actuators <NUM> couple rotatable the corresponding second skeleton portion <NUM> on the left or right side and the corresponding third skeleton portion <NUM> along the left or right lower leg portion of the user wearing the powered suit <NUM>. The ankle actuators <NUM> couple rotatable to the corresponding third skeleton portion <NUM> on the left or right side, and a corresponding shoe sole plate <NUM> provided on the underside of the foot harness <NUM> on the left or right side of the user wearing the powered suit <NUM>. The hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> are drive mechanisms that output torques that reduce the load on the user at each joint of each leg of the user.

The hip joint sensor <NUM> is installed in the hip actuator <NUM>, and detects the hip joint angle, that is, the angle formed between the first skeleton portion <NUM> and the second skeleton portion <NUM>, by an encoder. The knee joint sensor <NUM> is installed in the knee actuator <NUM>, and detects the knee joint angle, that is, the angle between the second skeleton portion <NUM> and the third skeleton portion <NUM>, by the encoder. The ankle joint sensor <NUM> is installed in the ankle actuator <NUM>, and detects the ankle joint angle, that is, the angle between the third skeleton portion <NUM> and the shoe sole plate <NUM>, by the encoder. The hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM> detect the angle of each joint of each leg of the user (hereinafter referred to as the "joint angle").

The user who wears the powered suit <NUM> attaches his/her left and right feet to the corresponding foot harnesses <NUM>, and fixes the first skeleton portion <NUM> to the waist with the belt <NUM> so that the first skeleton portion <NUM> is closely attached to the waist. The powered suit <NUM> has a structure in which most of the load of the luggage and the load of the powered suit <NUM> is released to the ground surface in contact with the soles of the feet via the skeleton portion <NUM> and the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. The user turns on the control device <NUM> of the powered suit <NUM>. The control device <NUM> controls the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> so as to transmit as much of the device weight as possible, which is the sum of the load of the luggage loaded on the loading platform <NUM> and the weight of the powered suit <NUM>, to the walking surface via the skeleton portion <NUM> and the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. Thereby, the powered suit <NUM> mitigates the burden such as the load of the luggage on the user who wears the powered suit <NUM> and performs various operations.

<FIG> is the first diagram showing the arrangement relationship between the shoe sole load sensor and the foot sole load sensor.

<FIG> is a second diagram showing the arrangement relationship between the shoe sole load sensor and the foot sole load sensor.

<FIG> shows a view when the foot harness <NUM> and each sensor of the right foot of <FIG> are visually recognized from the heel direction. <FIG> shows a view when the foot harness <NUM> and each sensor of the right foot of <FIG> are visually recognized from the inner thigh direction. As shown in <FIG>, the shoe sole load sensor <NUM> is provided on the bottom (sole) of the foot harness <NUM> corresponding to the shoe worn by the user. The shoe sole load sensor <NUM> is provided on the ground contact surface side of the shoe sole plate <NUM>, which transmits the weight F of the powered suit <NUM> and luggage to the ground contact surface, and the foot harness <NUM>, which transmits the user's weight to the ground contact surface, so as to cover the entire back surface of the shoe sole plate <NUM> and the foot harness <NUM>. The foot sole load sensor <NUM> is provided in the foot harness <NUM> so as to cover the entire surface of the sole so as to be able to measure the weight applied from the sole of the user. The foot sole load sensor <NUM> may be provided between the insole of the foot harness <NUM> and the shoe sole plate <NUM>.

<FIG> is a diagram showing the relationship between the areas of the shoe sole load sensor and the foot sole load sensor.

<FIG> is a view when the foot harness <NUM>, the shoe sole load sensor <NUM>, and the foot sole load sensor <NUM> are visually recognized from above. As shown in this figure, the shoe sole load sensor <NUM> has an area covering the entire ground contact surface (underside) of the foot harness <NUM> and the shoe sole plate <NUM>. Further, the foot sole load sensor <NUM> is provided inside the foot harness <NUM> so as to cover the entire underside of the foot. As shown in <FIG>, in one example the shoe sole plate <NUM> is provided so as to be sandwiched between the foot harness <NUM> and the shoe sole load sensor <NUM> in the width direction of the shoe sole load sensor <NUM>.

<FIG> is a diagram showing an outline of the load sensor.

As shown by the example in <FIG>, electrodes are arranged in a matrix on the front and back of a thin sheet-like insulator in the shoe sole load sensor <NUM> and the foot sole load sensor <NUM>. The shoe sole load sensor <NUM> and the foot sole load sensor <NUM> measure the electrical resistance of the lattice points of the electrodes, and output the measured values to the control device <NUM>. The control device <NUM> calculates the pressure applied to each lattice point and the load on the entire surface of the sensor sheet on the basis of the electrical resistance value of each lattice point. <FIG> shows the foot sole load sensor <NUM>.

<FIG> is a diagram showing the hardware configuration of the control device.

As shown in this figure, the control device <NUM> is a computer provided with hardware such as a CPU (Central Processing Unit) <NUM>, a ROM (Read Only Memory) <NUM>, a RAM (Random Access Memory) <NUM>, a signal input/output device <NUM>, and a wireless communication device <NUM>.

The signal input/output device <NUM> inputs signals output from the shoe sole load sensor <NUM>, the foot sole load sensor <NUM>, the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM>. The signal input/output device <NUM> outputs control signals for controlling the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. The control device <NUM> operates by power supplied from the battery <NUM>.

The wireless communication device <NUM> is communicatively connected with another device.

<FIG> is a function block diagram of the control device.

The control device <NUM> is activated based on the power supplied from the battery <NUM> when the power button is turned on. The control device <NUM> executes the control program after startup. As a result, the control device <NUM> is provided with at least the function configuration of an information acquisition unit <NUM>, an integrated control unit <NUM>, an actuator control unit <NUM>, a power supply unit <NUM>, and a storage unit <NUM>.

The information acquisition unit <NUM> acquires sensing information from the shoe sole load sensor <NUM>, the foot sole load sensor <NUM>, the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM>. The sensing information of the shoe sole load sensor <NUM> is shoe sole load information indicating the electrical resistance value corresponding to the pressure (load) at each lattice point described using <FIG>. The sensing information of the foot sole load sensor <NUM> is the sole load information indicating the electrical resistance value corresponding to the pressure (load) of each lattice point. The sensing information of the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM> is joint angle information indicating the detected joint angle.

The actuator control unit <NUM> controls the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>.

When the power button is turned on, the power supply unit <NUM> supplies electric power from the battery <NUM> to each part of the control device <NUM>.

The storage unit <NUM> stores an angle reference for each joint of the leg.

The integrated control unit <NUM> is provided with a ground reaction force load difference calculation unit <NUM> and a torque control unit <NUM>.

The ground reaction force load difference calculation unit <NUM> acquires a first measured value and a second measured value. The first measured value indicates a value at which a weight based on the weight of the powered suit <NUM> (load reduction device) and the weight of the user is transmitted to the ground contact surface. The powered suit <NUM> reduces the load on the user and is worn by at least the user. The second measured value indicates a value at which a weight based on the user's weight is transmitted to the ground contact surface.

The ground reaction force load difference calculation unit <NUM> calculates the ground reaction force load difference, which is the amount of load from which the user is to be relieved, based on the first measured value and the second measured value. The first measured value is the shoe sole ground reaction force load based on the shoe sole load information detected by the shoe sole load sensor <NUM>. The second measured value is the foot sole ground reaction force load based on the foot sole load information detected by the foot sole load sensor <NUM>. Further, the ground reaction force load difference calculation unit <NUM> calculates the ground reaction force load difference in a stance period by one foot after the landing of one foot in the gait cycle from the start to the end of the walking step.

The torque control unit <NUM> controls the output torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. The torque control unit <NUM> controls the output torque in order to reduce the load on the user at the leg joints of the user on the basis of the ground reaction force load difference calculated by the ground reaction force load difference calculation unit <NUM> and each joint angle of each leg detected by the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM>. The torque control unit <NUM> may control the output torque on the basis of the first measured value or the second measured value.

Next the operation of the control device <NUM> will be described in detail.

<FIG> is an operation block diagram showing the operation of the control device.

First, the ground reaction force load difference calculation unit <NUM> calculates the ground reaction force load difference on the basis of the first measured value (shoe sole ground reaction force load) based on the shoe sole load information detected by the shoe sole load sensor <NUM>, and the second measured value (foot sole ground reaction force load) based on the food sole load information detected by the foot sole load sensor <NUM>.

The ground reaction force load difference calculation unit <NUM> calculates, on the basis of the shoe sole load information, the first measured value (shoe sole ground reaction force load) applied to the shoe sole load sensor <NUM>, which is provided on the ground contact surface side of the shoe sole plate <NUM> and the foot harness <NUM> of the powered suit <NUM>. Specifically, the ground reaction force load difference calculation unit <NUM> calculates the pressure applied to each lattice point and the load on the entire surface based on the electrical resistance value of each lattice point included in the shoe sole load information, and finds the first measured value (shoe sole ground reaction force load) applied to the shoe sole load sensor <NUM>. The weight indicated by the first measured value is the weight, applied to the shoe sole load sensor <NUM>, which is a composite weight F' during walking of the weight of the user, the weight of the powered suit <NUM>, and the weight F of the luggage. More specifically, the first measured value is a value obtained by combining "the load (weight F of luggage) + the suit weight + the body weight + force caused by acceleration, etc.".

The ground reaction force load difference calculation unit <NUM> calculates, on the basis of the foot sold load information, the second measured value (foot sole ground reaction force load) applied to the foot sole load sensor <NUM> inserted in the foot harness <NUM> of the powered suit <NUM>. The second measured value (foot sole ground reaction force load) is the weight applied to the foot sole load sensor <NUM>, which is a composite weight f of the weight of the user and the load on the user (the weight that could not escape to the ground contact surface via the skeleton portion <NUM> among the luggage and the weight of the power suit). Specifically, the ground reaction force load difference calculation unit <NUM> calculates the pressure applied to each lattice point and the load on the entire surface based on the electrical resistance value of each lattice point included in the shoe sole load information, and finds the second measured value (foot sole ground reaction force load) applied to the foot sole load sensor <NUM>. More specifically, the second measured value is a value obtained by combining "a part of the load (weight F of the luggage) + a part of the suit weight + (a part of) the body weight + a part of the force caused by the acceleration, etc.".

The ground reaction force load difference calculation unit <NUM> calculates the ground reaction force load difference by subtracting the second measured value from the first measured value. This ground reaction force load difference is the weight directly applied to the ground contact surface via the skeleton portion <NUM> among the weight of the luggage and the weight of the powered suit. Moreover, by subtracting a value based on the weight of the powered suit <NUM>, the ground reaction force load difference calculation unit <NUM> may calculate, among the weight of the luggage only, the weight directly applied via the skeleton portion <NUM> to the ground contact surface during walking by the user.

<FIG> is a diagram showing an example of a ground reaction force load difference.

In this figure, the broken line <NUM> is a graph showing the transition of the first measured value indicating the shoe sole ground reaction force load in the gait cycle in which the start to the end of a walking step of one leg of the user is treated as one unit. The solid line <NUM> is a graph showing the transition of the second measured value indicating the foot sole ground reaction force load in the gait cycle. In the graph, the horizontal axis shows the percentage of time elapsed from the start to the end of one walking step in the gait cycle.

In this gait cycle, the period from <NUM>% to <NUM>% in this gait cycle indicates a stance period during which a foot is placed on the ground contact surface (the leg is being a stance). The period from <NUM>% to <NUM>% in this gait cycle indicates a swing period in which no load is applied to the shoe sole load sensor <NUM> and the foot sole load sensor <NUM> due to the foot being separated from the ground contact surface (ground surface) (the leg is being a swing). In the graph, the vertical axis indicates the load. The ground reaction force load difference calculation unit <NUM> calculates the ground reaction force load difference N by subtracting the second measured value at the time point T from the first measured value at any time point T in the stance period.

The ground reaction force load difference calculation unit <NUM> calculates the ground reaction force load difference between the left and right feet by the above processing. The ground reaction force load difference calculation unit <NUM> outputs the calculated ground reaction force load difference of both feet to the torque control unit <NUM>.

The torque control unit <NUM> performs the following series of processes using the current first measured value detected by the shoe sole load sensor <NUM>, the current second measured value detected by the foot sole load sensor <NUM>, the input ground reaction force load difference, the angle reference θk0 at each j oint, and the current joint angle θk0 detected by each of the hip joint sensor <NUM>, knee joint sensor <NUM>, and ankle joint sensor <NUM> of each leg. That is, the torque control unit <NUM> detects characteristics of the user's motion at the present time in real time, and sequentially estimates the motion of the powered suit <NUM> using an internally built-in overall motion estimation model of the powered suit <NUM>. Then, the torque control unit <NUM> calculates the target value of the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. That is, the torque control unit <NUM> uses the current first measurement value, the current second measurement value, the ground reaction force load difference, the angle reference θk0 of each j oint, and the current joint angle θk of each joint of each leg, calculates the target value of the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> of each leg on the basis of a preset motion estimation model.

For example, the torque control unit <NUM> calculates the target value of torque assuming that the ground reaction force load difference is reduced by the powered suit <NUM>. Further, the torque control unit <NUM> may determine whether each leg is in the swing state or the stance state by using the first measured value or the second measured value. The torque control unit <NUM> may calculate the output torque at each joint of each leg by using each joint angle based on the motion estimation model at the time of a swing or the motion estimation model at the time of a stance. The torque control unit <NUM> outputs the calculated target value of the torque of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> of each leg to the actuator control unit <NUM>.

The actuator control unit <NUM> controls the rotation angles of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> with an angle controller Kci(s) on the basis of the target value of each torque. "s" indicates the frequency domain of the control system. Subsequently, the actuator control unit <NUM> calculates the torque τ at the current timing in relation to the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> of each leg by a force controller Kbi(s), and outputs a signal indicating each torque τ to each of these actuators.

Thereby, the interaction force Fk between suits and person applied by the user in the kth of the time series (current value), the torque lk applied by the user, and the output torque τ become the dynamics P(s) of each actuator. The hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM> detect each joint angle θk in the kth of the time series in accordance with the dynamics G(s) of the powered suit <NUM> based on the dynamics P(s) of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. Then, the control device <NUM> repeats the above-described processing.

Note that the actuator control unit <NUM> calculates the torque τ using the following torque calculation formula as an example. In this torque calculation formula (<NUM>), "(θ) / G(s)" indicates a feedback factor to the actuator control unit <NUM>. "Fk·lk" indicates a feedforward factor. Ti indicates the target value of the torque calculated by the torque control unit. f(θ) indicates a function including an angle θ based on the angle reference of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. The torque calculation formula below is an example, and a formula other than the torque calculation formula shown below may be used. In the torque calculation formula (<NUM>), "s" indicates the frequency domain of the control system, Kbi indicates the control model of the force controller, and Kci indicates the control model of the angle controller.

<FIG> is a flowchart showing the processing of the powered suit.

First, the user wears the powered suit <NUM>. At this time, the user inserts the foot sole load sensor <NUM> inside the foot harness <NUM>. The foot sole load sensor <NUM> may be provided inside the foot harness <NUM> in advance. As the area of the foot sole load sensor <NUM>, a size suitable for the size of the user's foot may be used. Further, the user attaches the shoe sole load sensor <NUM> to the ground contact surface side of the foot harness <NUM> or the shoe sole plate <NUM> of the powered suit <NUM>. The shoe sole load sensor <NUM> may also be provided in advance on the ground contact surface side of the foot harness <NUM> or the shoe sole plate <NUM>. As the area of the shoe sole load sensor <NUM>, a size suitable for the foot harness <NUM> corresponding to the size of the user's foot may be used.

The user operates the power button of the control device <NUM> provided in the powered suit <NUM> to turn on the power. As a result, the control device <NUM> is started. The user performs motions such as walking, running, leaping, and jumping while wearing the powered suit <NUM>. The user may load luggage on the loading platform <NUM> of the powered suit <NUM> and perform operations such as walking, running, leaping, and jumping. The actuator control unit <NUM> of the control device <NUM> controls the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> so as to reduce the load on the user due to the weight of the luggage or the powered suit <NUM>. Thereby, the powered suit <NUM> tracks various motions of the user.

While the control device <NUM> is being driven, the information acquisition unit <NUM> acquires joint angle information from the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM> at predetermined intervals (Step S101). While the control device <NUM> is being driven, the information acquisition unit <NUM> acquires shoe sole load information from the shoe sole load sensor <NUM> at a predetermined interval (Step S102). Further, while the control device <NUM> is being driven, the information acquisition unit <NUM> acquires foot sole load information from the foot sole load sensor <NUM> at a predetermined interval (Step S103). As described above, the shoe sole load information and the foot sole load information are electrical resistance values corresponding to the pressures (loads) at the respective lattice points of the shoe sole load sensor <NUM> and the foot sole load sensor <NUM>. The predetermined interval is, for example, every short time such as every <NUM> milliseconds.

The ground reaction force load difference calculation unit <NUM> calculates the ground reaction force load difference by subtracting the second measured value (foot sole ground reaction force load) indicated by the foot sole load information from the first measured value (shoe sole ground reaction force load) indicated by the shoe sole load information (Step S104). The torque control unit <NUM> calculates the target value of the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and an ankle actuator <NUM> of each leg based on the first measured value, the second measured value, the ground reaction force load difference, the angle reference of each j oint, and the j oint angle of each join (Step S105).

The actuator control unit <NUM> outputs, to each actuator, a signal (τ) for causing the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> of each leg to output each torque of the target value of the torque calculated by the torque control unit <NUM> (Step S106). After that, the processing returns to the process of Step S101, and the control device <NUM> repeats the processes from steps S101 to S106 until the processing is completed.

According to the above processing, the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> is controlled on the basis of the ground reaction force load difference obtained by subtracting the second measured value in which the weight based on the weight of the user is transmitted to the ground contact surface, from the first measured value in which the weight, based on the weight of the powered suit <NUM> and the weight of the user, is transmitted to the ground contact surface. As a result, the control device <NUM> of the powered suit <NUM> can directly control the load reduction in consideration of the load relief amount for the user (the state in which the load is reduced by the powered suit <NUM>). Therefore, more appropriate user load reduction can be realized.

Further, when a device other than the powered suit <NUM> performs the above-mentioned processing, the real-time property may be impaired due to a delay in data transmission/reception. However, in the present embodiment, since the control device <NUM> included in the powered suit <NUM> executes the above-mentioned processing, it is possible to respond to a sudden operation of the user without delay.

Although the embodiment of the present invention has been described above, the shoe sole load sensor <NUM> may be provided in advance on the ground contact surface side of the shoe sole plate <NUM> of the powered suit <NUM>. Also, the foot sole load sensor <NUM> may be inserted in advance inside the foot harness <NUM>.

In the above description, it was shown that the shoe sole load sensor <NUM> has an area covering the entire underside of the foot harness <NUM>, and the foot sole load sensor <NUM> has an area covering the entire underside of the foot in the foot harness <NUM>. However, the shoe sole load sensor <NUM> may be capable of measuring the load applied to the ground contact surface from the shoe sole plate <NUM> or the foot harness <NUM> even when the position where the load is applied deviates.

For example, the shoe sole load sensor <NUM> may be a plurality of pressure sensors provided on the ground contact surface side of the shoe sole plate <NUM>. Even if the load point on the ground contact surface of the shoe sole plate <NUM> moves over time, the plurality of pressure sensors sequentially measure the load at each load point, and output the shoe sole load information including the electrical resistance value corresponding to that load.

The foot sole load sensor <NUM> may also be composed of a plurality of pressure sensors. Even when the load position of the sole in the foot harness <NUM> moves with the passage of time, the plurality of pressure sensors sequentially measure the load and output the foot sole load information including the electric resistance value corresponding to the load.

The ground reaction force load difference calculation unit <NUM> may calculate the first measured value, the second measured value, and the ground reaction force load difference based on the shoe sole load information and the foot sole load information obtained from these plurality of sensors.

The ground reaction force load difference calculation unit <NUM> may calculate the load corresponding to the sensing information by machine learning based on past shoe sole load information and foot sole load information and store the load in the storage unit <NUM>. In this case, the ground reaction force load difference calculation unit <NUM> may read the loads (shoe sole ground reaction force load and foot sole ground reaction force load) corresponding to the electric resistance values indicated by the shoe sole load information and the foot sole load information from the storage unit <NUM> for use in calculation of the ground reaction force load difference.

The arrangement relationship between the shoe sole load sensor <NUM> and the foot sole load sensor <NUM> is not limited to the above.

<FIG> are diagrams showing other arrangement examples of the shoe sole load sensor and the foot sole load sensor.

<FIG> shows a view when the foot harness <NUM> and each sensor of the right foot are visually recognized from the heel direction.

<FIG> shows a view when the foot harness <NUM> and each sensor of the right foot of <FIG> are visually recognized from the inner thigh direction.

These <FIG> differ from <FIG> in that a protective sheet <NUM> is provided so as to cover the entire underside of the shoe sole load sensor <NUM>. Further, the shoe sole plate <NUM> is embedded in a sole <NUM> of the foot harness <NUM>. Further, the ground contact portion of the foot harness <NUM> has a flatter shape. The protective sheet <NUM> is provided on the underside of the shoe sole load sensor <NUM>. The protective sheet <NUM> may be provided so as to sandwich the shoe sole load sensor <NUM> vertically. By protecting the shoe sole load sensor with the protective sheet <NUM>, the durability of the shoe sole load sensor <NUM> can be improved, and there is an effect that problems such as damage during measurement can be prevented.

Further, in the above example, the control device <NUM> is provided in the powered suit <NUM>, but the present invention is not limited thereto, and another device that is communicatively connected with the powered suit <NUM> by wires or wirelessly may have the function of the control device <NUM>.

<FIG> is a diagram showing the minimum configuration of the control device.

The minimum configuration of the load reduction device is the control device <NUM>. The control device <NUM> may have at least the functions of the ground reaction force load difference calculation unit <NUM> and the torque control unit <NUM> described above.

The ground reaction force load difference calculation unit <NUM> calculates a ground reaction force load difference, which is the amount of load from which the user is to be relieved, on the basis of a first measured value in which a weight, based on the weight of the load reduction device and the weight of the user, is transmitted to the ground contact surface, and a second measured value in which a weight based on the weight of the user is transmitted to the ground contact surface. The load reduction device reduces the load on the user and at least has a mechanism for holding the load worn by the user.

The torque control unit <NUM> controls the output torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> in order to reduce the load on the user at the joints of the user's legs on the basis of the ground reaction force load difference calculated by the ground reaction force load difference calculation unit <NUM>.

The above-mentioned control device <NUM> may also be a computer provided with hardware such as the CPU (Central Processing Unit) <NUM>, the ROM (Read Only Memory) <NUM>, the RAM (Random Access Memory) <NUM>, an HDD (Hard Disk Drive) <NUM>, and the wireless communication device <NUM>.

The control device <NUM> described above has a computer system inside. The process of each processing described above is stored in a computer-readable recording medium in the form of a program, with the process being performed by the computer reading and executing this program. Here, the computer-readable recording medium refers to a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Further, this computer program may be distributed to a computer via a communication line, and the computer receiving the distribution may execute the program.

Further, the above-mentioned program may be for realizing some of the functions described above.

Moreover, the above-mentioned program may be a so-called differential file (differential program) that can realize the above-mentioned functions in combination with a program already recorded in the computer system.

Claim 1:
A load reduction device (<NUM>) comprising:
a ground reaction force load difference calculation unit (<NUM>) configured to
acquire, based on a value detected by a shoe sole load sensor (<NUM>), a first measured value at which a weight based on a weight of a powered suit or skeleton (<NUM>) worn by a user and a weight of the user is transmitted to a ground contact surface, the shoe sole load sensor (<NUM>) being provided on a side of the ground contact surface of a shoe sole plate (<NUM>) that is provided on an underside of a foot harness (<NUM>), or a side of the ground contact surface of the foot harness (<NUM>),
acquire, based on a value detected by a foot sole load sensor (<NUM>) that is inserted in the foot harness (<NUM>), a second measured value at which a weight based on the weight of the user is transmitted to the ground contact surface, and
calculate a ground reaction force load difference that is an amount of a load relief for the user, on the basis of the acquired first measured value and the acquired second measured value; and
a torque control unit (<NUM>) configured to control, on the basis of the ground reaction force load difference, torque that is output by a drive mechanism of the load reduction device (<NUM>) to reduce the load on the user at a joint of each leg of the user.