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

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> describes a motion assist device capable of preventing collapse of an actuator in seating. Patent Document <NUM> discloses a technique for determining the magnitude of drive torque to be generated in a rotation drive part, based on the user's motion detected by a six-axis sensor including a three-axis acceleration sensor and a three-axis gyro sensor for detecting the wearer's motion, and the rotation angle of each of the rotation drive parts. Patent Document <NUM> describes a walking support device that mitigates the impulsive force due to mechanical play that occurs when the operation is reversed.

<CIT> relates to a motion assistance apparatus. The motion assistance apparatus includes a proximal support configured to support a proximal part of a user and a distal support configured to support a distal part of the user.

<CIT> discloses an exoskeleton comprising shock absorption bodies of adjustable length provided in the thigh and calw links, wherein the torque output of the joint drivers is controlled in a shock absorption mode on the basis of an equation that takes into account the length of the thigh and calw links during operation of the shock absorption mechanism.

However, in the techniques described in Patent Documents <NUM> to <NUM>, when the user performs agile movements such as running or jumping, a very large torque corresponding to a large impact generated when the user makes contact with the ground is required for each joint. For that reason, the motors and batteries of the actuators for each joint tend to be larger and heavier. Therefore, the problem arises of the load reduction device becoming large and heavy, making it difficult for the user to handle easily.

An object of the present invention is to provide a load reduction device, a load reduction method, and a program that can solve the above-mentioned problems.

According to a first aspect of the present invention, a load reduction device according to claim <NUM> is provided.

According to a second aspect of the present invention, a load reduction method according to claim <NUM> is provided.

According to a third aspect of the present invention, a program according claim <NUM> causing a computer of a load reduction device to execute processes is provided.

According to the present invention, it is possible to reduce the size and weight of the load reduction device.

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

First, the first embodiment of the present invention will be described.

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

The powered suit <NUM> is one 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>, a foot sole load sensor <NUM>, 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 configured as follows so as to support the loading platform <NUM>, which is one aspect of the mechanism for holding luggage as an example. That is, the powered suit <NUM> is provided with the first skeleton portion <NUM>, and 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 back 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 <NUM> that output torque for rotationally driving a link (frame) connected at each joint of each leg of the user to reduce the load on the user. The first skeleton portion <NUM> and the second skeleton portion <NUM> are links to which the hip actuator <NUM> is connected. The second skeleton portion <NUM> and the third skeleton portion <NUM> are links to which the knee actuator <NUM> is connected. Further, the third skeleton portion <NUM> and the shoe sole plate <NUM> are links to which the ankle actuator <NUM> is connected. Each link and drive mechanism <NUM> constitute a link mechanism.

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 shoe sole load sensor <NUM> is provided on the bottom 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> that transmits the weight of the powered suit <NUM> and luggage to the ground contact surface, and the foot harness <NUM> that 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 sole surface so as to be able to measure the weight applied from the sole of the user. For example, the foot sole load sensor <NUM> may be provided between the insole of the foot harness <NUM> and the shoe sole plate <NUM>.

As an example, 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.

The user who wears the powered suit <NUM> puts his/her left and right feet into 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 motions.

<FIG> is a diagram showing an example of the shock absorption mechanism according to the present embodiment.

The powered suit <NUM> is provided with a shock absorption mechanism <NUM> that can disperse the impact force in time by absorbing the impact force generated during the motion of the user. The shock absorption mechanism <NUM> is an elastic mechanism in which a spring and a dashpot, which are elastic bodies, are arranged in parallel or in series. As one example, the shock absorption mechanism <NUM> is roughly classified into a first shock absorption mechanism <NUM> provided in the second skeleton portion <NUM> and a second shock absorption mechanism <NUM> provided in the third skeleton portion <NUM>. The first shock absorption mechanism <NUM> expands and contracts in the direction D1 along the second skeleton portion <NUM>. The second shock absorption mechanism <NUM> expands and contracts in the direction D2 along the third skeleton portion <NUM>. Thereby, the shock absorption mechanism <NUM> absorbs shocks applied to the legs and disperses the shocks in time.

<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> by turning on the power button. The control device <NUM> executes a control program after startup. As a result, the control device <NUM> is provided with at least 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> and the foot sole load sensor <NUM> is load information indicating the electrical resistance value corresponding to the pressure (load) at the lattice points of each sensor. 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 at each joint of the leg.

The integrated control unit <NUM> is provided with an operation estimation unit <NUM> and a torque control unit <NUM> of the shock absorption mechanism.

The operation estimation unit <NUM> estimates the state of the shock absorption mechanism <NUM> on the basis of the operation of the shock absorption mechanism <NUM>. For example, the operation estimation unit <NUM> calculates a load value corresponding to a buffered impact on the basis of a preset operation estimation model of the shock absorption mechanism <NUM> as the state of the shock absorption mechanism <NUM>, and outputs estimation information indicating the calculated load value to the torque control unit <NUM>.

The torque control unit <NUM> controls the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> based on the operation of the shock absorption mechanism <NUM>. For example, the torque control unit <NUM> subtracts the load value indicated by the estimation information input from the operation estimation unit <NUM> from the load value applied to the sole or shoe sole as the impact cushioned by the shock absorption mechanism <NUM>. The torque control unit <NUM> calculates a target value of the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> based on the load value after subtraction and the joint angles detected by the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM>.

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 according to the present embodiment.

First, the operation estimation unit <NUM> estimates the state of the shock absorption mechanism <NUM> on the basis of the operation estimation model of the shock absorption mechanism <NUM> set in advance. Specifically, the operation estimation unit <NUM> estimates the state of the shock absorption mechanism <NUM> by the operation estimation model on the basis of the shock absorption mechanism information indicating the operating status of the shock absorption mechanism <NUM>, load values of each leg detected by the shoe sole load sensor <NUM> or the foot sole load sensor <NUM>, and the joint angle θk detected by the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM> of each leg. The shock absorption mechanism information includes, for example, the spring length indicating the current length of the spring, the dashpot length indicating the current length of the dashpot, the expansion/contraction speed of the spring and the dashpot, and the load values applied to the spring and the dashpot. The operation estimation unit <NUM> estimates, for example, a load value corresponding to the buffered impact as the state of the shock absorption mechanism <NUM>. Then, the operation estimation unit <NUM> outputs the estimation information indicating the estimated state of the shock absorption mechanism <NUM> to the torque control unit <NUM>.

The torque control unit <NUM> performs the following series of processes using the estimation information input from the operation estimation unit <NUM>, a load value of each leg detected by the shoe sole load sensor <NUM> or the foot sole load sensor <NUM>, the joint angle θk detected by the hip joint sensor <NUM>, the knee joint sensor <NUM>, and the ankle joint sensor <NUM> of each leg, and the angle reference θk0 of each joint. 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 operation of the powered suit <NUM> by using the operation estimation model of the entire powered suit <NUM> built-in inside. Then, the torque control unit <NUM> calculates target values of the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. That is, using the estimation information, the current load values, the angle reference θk0 of each joint, and the current joint angle θk of each joint of each leg, the torque control unit <NUM> calculates the target values 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 the preset operation estimation model.

For example, the torque control unit <NUM> may use the load values to determine whether each leg is in the swing state or the stance state. As an example, the torque control unit <NUM> makes a determination of a stance period when the load value is equal to or greater than the first threshold value, and makes a determination of a swing period when the load value is equal to or less than the second threshold value. Further, the torque control unit <NUM> subtracts the load value included in the estimation information from the load value of each leg detected by the shoe sole load sensor <NUM> or the foot sole load sensor <NUM> as an impact buffered by the shock absorption mechanism <NUM>. Then, based on the operation estimation model during the swing phase or the operation estimation model during the stance phase, the torque control unit <NUM> uses the load value of each leg after subtraction and the joint angles of each leg to calculate the target value of the torque at each joint of each leg. The torque control unit <NUM> outputs the calculated target values of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> 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 values. "s" indicates the frequency domain of the control system. Subsequently, the actuator control unit <NUM> calculates the torque τ at the current timing for the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> of each leg by the 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, the applied torque lk applied by the user, and the output torque τ in the kth of the time series (current value) 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 according to 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 graph illustrating the transition of joint torque in the gait cycle according to the present embodiment.

In this figure, the solid line <NUM> shows the transition of the joint torque when the shock absorption mechanism <NUM> is not provided in the gait cycle in which the start to the end of the walking step of the user is one unit. The joint torque is a target value (unit: Nm (Newton meter)) of the torque output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> at each joint. The solid line <NUM> shows the transition of the joint torque when the shock absorption mechanism <NUM> is provided in the gait cycle. In the graph, the horizontal axis shows the percentage of time elapsed from the start to the end of the walking step of the gait cycle. The period from <NUM>% to <NUM>% in this gait cycle indicates the stance period in which the foot is placed on the ground plane (the leg is erected). The period from <NUM>% to <NUM>% in this gait cycle shows the swing period in which no load is applied to the shoe sole load sensor <NUM> and the foot sole load sensor <NUM> (the leg is being a swing) due to the foot being separated from the ground contact surface (ground). In the graph, the vertical axis shows the joint torque.

When the shock absorption mechanism <NUM> is not provided, the joint torque at peak time T is τ1, whereas when the shock absorption mechanism <NUM> is provided, the joint torque at peak time T is τ2, which is less than half of τ1. This is because the shock absorption mechanism <NUM> absorbs the energy of the shock from the ground and transmits the energy to the ground, whereby the energy can be dispersed in the time before and after as shown by the arrow <NUM>. As a result, the joint torque required at peak time T can be reduced.

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

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 off while wearing the powered suit <NUM>. The user may load luggage on the loading platform <NUM> of the powered suit <NUM> and perform motions 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). Further, while the control device <NUM> is being driven, the information acquisition unit <NUM> acquires load information from the shoe sole load sensor <NUM> and the foot sole load sensor <NUM> at predetermined intervals (Step S102). In addition, while the control device <NUM> is being driven, the information acquisition unit <NUM> acquires acceleration information from the shock absorption mechanism <NUM> (Step S103). The predetermined interval is, for example, every short time such as every <NUM> milliseconds.

The operation estimation unit <NUM> estimates the state of the shock absorption mechanism <NUM> based on the shock absorption mechanism information, the joint angle information, and the load information (Step S104). The torque control unit <NUM> calculates the target value of the output torque output by the hip actuator <NUM>, the knee actuator <NUM> and the ankle actuator <NUM> of each leg on the basis of the load value applied to each leg, the angle reference of each joint, and the joint angle of each joint of each leg (Step S105).

The actuator control unit <NUM> calculates each torque τ at the current timing based on the torque target values calculated for the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> of each leg, and outputs to the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> (Step S106). After that, the process returns to the process of Step S101, and the control device <NUM> repeats the processes from steps S101 to S106 until the process is completed.

According to the above processing, even when a large impact is applied to the powered suit <NUM>, the impact is cushioned by the shock absorption mechanism <NUM>, and transmitted to the hip actuator <NUM>, the knee actuator <NUM> and the ankle actuator <NUM> of each joint via the frame of the link mechanism. Therefore, the required torque at the peak is reduced. Further, the torque control unit <NUM> calculates the required torques of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> based on the operation of the shock absorption mechanism <NUM>. Therefore, the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> can output a more optimum and accurate required torque for the entire powered suit <NUM> in consideration of the operation of the shock absorption mechanism <NUM>. By adopting this arrangement, the maximum torque value output by the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> of each joint can be reduced. For that reason, the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> can be made smaller and lighter. Therefore, the entire powered suit <NUM> can be made smaller and lighter, which makes handling easier for the user.

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

Next, the second embodiment will be described.

The powered suit <NUM> in the present embodiment is provided with a shock absorption mechanism <NUM> in addition to the shock absorption mechanism <NUM> of the first embodiment. The shock absorption mechanism <NUM> is a mechanism that can disperse a shock in time by absorbing the shock generated during a motion of the user. The shock absorption mechanism <NUM> is an elastic mechanism in which a spring and a dashpot, which are elastic bodies, are arranged in parallel or in series. The shock absorption mechanism <NUM> is provided at a position where luggage B of the loading platform <NUM> is loaded. That is, the shock absorption mechanism <NUM> is provided at a position corresponding to the back of the user. The luggage B is loaded on the shock absorption mechanism <NUM>. The shock absorption mechanism <NUM> expands and contracts in the direction D11 along the back of the user (the back portion of the loading platform <NUM>). As a result, the shock absorption mechanism <NUM> absorbs shocks applied to the legs and disperses the shocks in time. Since other configurations of the powered suit <NUM> are the same as those of the first embodiment, descriptions thereof will be omitted.

Next, the third embodiment will be described.

<FIG> and <FIG> are diagrams showing an example of the shock absorbing mechanism according to the present embodiment.

As shown in <FIG>, the powered suit <NUM> in this embodiment is provided with a shock absorption mechanism <NUM> in addition to the shock absorption mechanism <NUM> of the first embodiment. The shock absorption mechanism <NUM> is a mechanism that can disperse a shock in time by absorbing the shock generated during a motion of the user. As shown in <FIG>, the shock absorption mechanism <NUM> is a counter-balance mechanism that achieves balance by causing two counters <NUM> and <NUM> to rotate around a rotation shaft <NUM>. The shock absorption mechanism <NUM> is provided on the loading platform <NUM> or the luggage B. That is, the shock absorption mechanism <NUM> is provided at a position corresponding to the back of the user. The counter <NUM> rotates in the direction of arrow D21. The counter <NUM> rotates in the direction of arrow D22. As a result, the shock absorption mechanism <NUM> absorbs shocks applied to the legs and disperses the shocks in time. The shock absorption mechanism information in the present embodiment is the rotation angle, the rotation angular velocity, the additional centrifugal force, and the like of each counter <NUM>, <NUM>. Since other configurations of the powered suit <NUM> are the same as those of the first embodiment, descriptions thereof will be omitted.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made within a scope not departing from the scope of the present invention as defined in the appended claims.

For example, the shoe sole load sensor <NUM> may be provided in advance on a side of the ground contact surface of the shoe sole plate <NUM> of the powered suit <NUM>. Further, the foot sole load sensor <NUM> may be inserted in advance inside the foot harness <NUM>.

Further, in the above description, it was shown that the shoe sole load sensor <NUM> has an area that covers the entire back surface of the foot harness <NUM>, and the foot sole load sensor <NUM> has an area that covers the entire sole in the inner part of 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.

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>.

Further, in the above description, the powered suit <NUM> is provided with the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM> corresponding respectively to each joint, but is not limited thereto. The powered suit <NUM> may have at least one of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>. For example, the powered suit <NUM> may be provided with only the hip actuator <NUM> and the knee actuator <NUM>, and does not have to be provided with the ankle actuator <NUM>. Alternatively, the ankle actuator <NUM> may be an actuator that does not use a control signal, such as a mechanical leaf spring. In this case, the ankle joint sensor <NUM> is an angle detection sensor that detects the bending angle of the leaf spring or a force sensor that detects the reaction force of the leaf spring. The torque control unit <NUM> calculates the target value of the torque output by the hip actuator <NUM> and the knee actuator <NUM> based on the bending angle of the leaf spring or the reaction force of the leaf spring detected by the ankle joint sensor <NUM>.

Further, in the above description, the powered suit <NUM> is provided with both the shoe sole load sensor <NUM> and the foot sole load sensor <NUM>, but is not limited thereto, and either one of the shoe sole load sensor <NUM> and the foot sole load sensor <NUM> may be provided.

<FIG> is a diagram showing the minimum configuration of the powered suit.

The powered suit <NUM> as one aspect of the load reducing device may have at least the functions of a shock absorption mechanism <NUM>, the drive mechanism <NUM> and the torque control unit <NUM>.

The shock absorption mechanism <NUM> absorbs impact force generated when a user moves and thereby disperses the impact force in time. The shock absorption mechanism <NUM> is a general term for the shock absorption mechanism, whereby either the shock absorbing mechanism <NUM> alone or in combination with the shock absorbing mechanisms <NUM> and/or <NUM> may be used.

The drive mechanism <NUM> outputs torque for reducing the load applied to the user at the joints of the user's legs. The drive mechanism <NUM> is any one or any combination of the hip actuator <NUM>, the knee actuator <NUM>, and the ankle actuator <NUM>.

The torque control unit <NUM> controls the torque output by the drive mechanism <NUM> on the basis of the operation of the shock absorption mechanism <NUM>.

The minimum configuration of the control device <NUM> may be provided with at least the function of the torque control 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 comprising:
a shock absorption mechanism (<NUM>, <NUM>, <NUM>, <NUM>) in which an elastic body is arranged to absorb impact force generated when a user moves;
a drive mechanism (<NUM>) configured to output torque for reducing a load applied to the user at a joint of a leg of the user; and
a torque control unit (<NUM>) configured to control the torque output by the drive mechanism on the basis of operation of the shock absorption mechanism,
wherein the shock absorption mechanism (<NUM>, <NUM>) has a first shock absorption mechanism (<NUM>) provided in a skeleton portion (<NUM>) corresponding to a thigh of the user and a second shock absorption mechanism (<NUM>) provided in a skeleton portion (<NUM>) corresponding to a lower leg of the user,
the first shock absorption mechanism (<NUM>) is configured to expand and contract in a first direction along the skeleton portion (<NUM>) corresponding to the thigh, and the second shock absorption mechanism (<NUM>) is configured to expand and contract in a second direction along the skeleton portion (<NUM>) corresponding to the lower leg, and
the skeletal portion (<NUM>) corresponding to the thigh and the skeletal portion (<NUM>) corresponding to the lower leg are rotatably coupled, and
wherein the shock absorption mechanism (<NUM>, <NUM>) is configured to estimate a state of the shock absorption mechanism based on load information indicating load values of each leg, and joint angle information indicating an angle of the joint, and shock absorption mechanism information indicating an operating status of the shock absorption mechanism, which includes at least one of a length of the elastic body, an expansion/contraction speed of the elastic body, or a load value applied to the elastic body, and
the torque control unit (<NUM>) is configured to control the torque based on the estimated state of the shock absorption mechanism, the load information, and the joint angle information.