Method and apparatus for controlling a force assist apparatus
United States Patent No.5,551,308
[Inventors]
Hirohiko Arai, Kazuo Tanie, Yasuo Hayashibara
[Applicant]
Agency of Industrial Science & Technology, Ministry of International Trade, Tokyo, Japan
[Issued/Filed Dates]
Sept. 3, 1996 / July 5, 1995
[Application Number]
US1995000498486
[IPC Class]
G01L 001/00;
[Priority Number]
JP1994000177471
[Abstract]
A method of controlling a force assist apparatus worn on a human body comprises separating a force signal relating to a load force imposed on the force assist apparatus detected by a force sensor into a static force component and a dynamic force component, attenuating the static force by a smaller factor than the factor by which the dynamic force is attenuated, attenuating the dynamic force by a factor within a range according to actuator output margin in which saturation does not occur, summing the attenuated signals, subtracting an operating force signal detected by a force sensor from the sum, and using the total signal as an output command to drive actuators.
[Claims]
What is claimed is:
1. A method of controlling a force assist apparatus worn on a human body, comprising:
- separating a force signal relating to a load force imposed on the force assist apparatus detected by a force sensor into a static force component and a dynamic force component,
- attenuating the static force by a smaller factor than the factor by which the dynamic force is attenuated,
- attenuating the dynamic force by a factor within a range according to actuator output margin in which saturation does not occur,
- summing the attenuated signals, subtracting an operating force signal detected by a force sensor from the sum, and
- using the total signal as an output command to drive actuators.
2. A control method according to claim 1, wherein the static force attenuation factor and the dynamic force attenuation factor can be changed independently and, prior to driving the force assist apparatus, the static force exerted on the work load is detected beforehand and attenuation factors are set with respect to load inertia and static and dynamic forces on the load.
3. An apparatus for controlling a force assist apparatus worn on a human body, comprising:
- two force sensors that detect operating and load forces imposed on the force assist apparatus,
- a force separation section that separates a detected load force signal from the force sensor into a static force component and a dynamic force component,
- two attenuater sections that individually attenuate the static and dynamic force components by a separate factor,
- an adder section that sums outputs of the two attenuater sections,
- a subtracter section that subtracts a detected operating force signal from the force sensor, and
- a control section that applies a subtracter section output signal as an actuator drive signal.