JPS6241024B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power prosthetic leg in which a hydraulic drive device drives the knee joint of a prosthetic leg worn by a disabled person who has had one or both legs amputated from the thigh.

Conventionally, there has been a device of this type as shown in FIG. In FIG. 1, 1 is a socket into which the stump is inserted, 2 is a thigh pipe, 3 is a knee joint, 4 is a lower leg pipe, 5 is a foot, and 3' is a pivot of the knee joint 3.

In this prosthetic leg, the patient walks by swinging out the crural pipe 4 with the foot 5 as a pendulum around the pivot 3' of the knee joint 3, and by applying his weight to the prosthetic leg after the foot 5 lands on the ground. However, with this conventional prosthetic leg, the walking speed cannot be changed because it is determined by the period of the pendulum determined by the mass of the foot 5 and the length of the crural pipe 4. Furthermore, if the force applied to the knee joint 3 is not on the same line as the lower leg pipe 4, the knee joint 3 will rotate and cause what is called a mid-fold, causing the wearer to fall over, making it impossible to go up and down stairs and slopes. was. In order to eliminate these drawbacks of conventional prosthetic legs, a powered prosthetic leg in which the knee joint is hydraulically driven has been proposed, and such a powered prosthetic leg is shown in FIG. 7 in Figure 2
9 is a hydraulic drive device for the knee, 9 is a hydraulic pump, 10 is a hydraulic pressure accumulator, 11 is a hydraulic drive device for an ankle, 8 is a control circuit that controls the hydraulic drive devices 7 and 11 according to their respective walking patterns, and 12 is a residual limb. Electrodes 6 for detecting myoelectric signals in the foot are suitable power sources such as batteries for hydraulic drives 7, 11, control circuits 8, etc.

Next, referring to FIG. 3, the electrodes 12 detect myoelectric signals corresponding to walking modes such as walking on flat ground and walking on stairs, and in response to this detection signal, the determining circuit 81 determines the walking mode. Based on the output, a walking pattern signal corresponding to the walking mode is sent from the pattern signal generation circuit 82 to each hydraulic drive device 7, 1.
1 and drives each hydraulic drive device 7, 11 in accordance with the pattern signal to perform walking.

However, with conventional powered prostheses, when going up and down stairs, the knee joints are wide open even when the steps are small, creating a pattern to prevent tripping. This has the disadvantage that the gait when walking on stairs becomes unnatural and the walking speed becomes slow.

This invention was made in order to eliminate the above-mentioned drawbacks, and the prosthetic leg when going up and down stairs is controlled by detecting the knee joint angle at the time of landing. In several steps, the joint angle of the next step is determined based on the knee joint angle of the previous step, and after that, the hydraulic drive device for the knee is repeatedly operated at the joint angle (i.e., walking pattern) determined in the last step. The purpose of the present invention is to provide a powered prosthetic leg that can move up and down stairs at a high speed with a natural gait. An embodiment of the present invention will be described below with reference to FIGS. 4 and 5.

FIG. 4 shows a powered prosthetic leg according to the present invention, where 13 is a knee angle sensor and 14 is a landing detection device provided at the bottom of the foot 5. The operation of the control circuit 8 is shown in the flowchart of FIG. That is, the determination circuit 81 detects the point in time when the walking mode switches to stair walking based on the signal from the electrode 12, and sends this detection signal to the command circuit 83 to determine the knee joint angle with respect to the first step of the prosthetic leg. Generates a pattern that moves significantly. When the prosthetic leg lands with the first step, it is detected by the landing detection device 14, and the detection signal is sent to the knee joint angle reading circuit 84 together with the output of the knee angle sensor 13, where it is detected when the prosthetic leg lands with the first step. The knee joint angle at the time is read. A signal indicating the read knee joint angle is sent to a walking pattern determining circuit 85, which determines the joint angle of the second step of the prosthetic leg based on the knee joint angle when the prosthetic leg lands on the first step. For example, during the first step, the knee joint is flexed greatly in anticipation of dealing with a larger step, so even if the knee joint angle is extended to θ ₀ , which should be the natural landing position in the walking pattern, the knee joint will not be able to land. The knee then continues to extend and lands only after reaching a smaller knee joint angle _θ1 . In this case, it is considered that the bending of the walking pattern at the first step is excessive than that suitable for walking on the stairs, so (joint angle of the walking pattern at the first step) × (θ ₁ / The walking pattern obtained by reducing the bending angle as θ ₀ ) is set as the walking pattern for the second step, and the knee hydraulic drive device 7 is driven by this walking pattern signal. To determine such a walking pattern, the third step is determined based on the second step of the prosthetic leg, the fourth step is determined based on the third step, and so on, and the signals are processed during the first few steps. Generally, stairs have almost constant steps, so the above operation is repeated for the first two, three or several steps of the prosthetic leg, and then the knee hydraulic pressure is adjusted according to the finally determined walking pattern. The drive device 7 is driven.

From the wearer's perspective, the first step of a prosthetic leg is the first step of the stairs, and the second step is the third step, so the step difference between the first and second steps is different, so the walking pattern determination circuit In step 85, the knee joint angles for the next two stages are determined based on the knee joint angle of the first stage.
However, in this case, the first step of the prosthetic leg is limited to the first step of the stairs, so a selection switch is provided on the prosthetic leg so that the first step can be selected as either the first step or the second step. If the walking pattern determining circuit 85 is also set to operate according to the selection made by the selection switch, it can be used in any case.

Some prosthetic legs are equipped with an ankle hydraulic drive device 11 as shown in the figure, while others are not.If the prosthetic leg is provided with an ankle hydraulic drive device 11, the ankle hydraulic drive device 11 is similar to the knee hydraulic drive device. Similarly, walking patterns can be determined. In any case, according to the present invention, in order to drive and control the knee hydraulic drive device 7, the first few steps of the changed walking mode are determined based on the knee joint angle of the previous step, and thereafter, the first few steps are determined based on the knee joint angle of the previous step. Since the control is repeated based on the walking pattern obtained at the end of several steps, this fixed pattern has the effect of shortening the signal processing time, increasing the walking speed, and making the gait more natural. .

[Brief explanation of the drawing]

Figure 1 is a diagram showing a conventional prosthetic leg, Figure 2 is a diagram showing a conventional powered prosthetic leg, Figure 3 is a flow chart showing the operation of the control circuit used in the powered prosthetic leg shown in Figure 2, and Figure 4 is a diagram showing the operation of the control circuit used in the powered prosthetic leg shown in Figure 2. A diagram showing a powered prosthesis according to the invention,
FIG. 5 is a flowchart showing the operation of the control circuit used in the power prosthesis shown in FIG. 4, and the same reference numerals in the figure indicate the same or equivalent parts. In the figure, 7 is a hydraulic drive device for the knee, 8 is a control circuit, 1
3 is a knee angle sensor, and 14 is a landing detection device.

Claims (1)

[Scope of Claims] 1. A powered prosthetic leg that drives a knee hydraulic drive device in accordance with a walking pattern signal from a control circuit, which includes a knee angle sensor that detects the knee joint angle when going up and down stairs, and a knee angle sensor that detects the knee joint angle when going up and down stairs. a landing detection device disposed at the bottom of the foot, the control circuit detecting a landing detected by the knee angle sensor when the landing detection device detects a landing in a previous step for a first desired number of steps of the prosthetic leg; The joint angle of the next step is determined based on the knee joint angle to determine the walking pattern for the knee hydraulic drive device, and after the desired number of steps, the step finally determined by the previous step is performed. A powered prosthetic leg, characterized in that the knee hydraulic drive device is driven repeatedly in a pattern. 2. The control circuit is capable of arbitrarily changing the initial desired number of stages of the prosthesis.
Power prosthesis as described in section.