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Is equilibrium point control feasible for fast goal-directed single-joint movements?
Dinant A Kistemaker1, Arthur J Van Soest, Maarten F Bobbert
1Institute for Fundamental and Clinical Human Movement Sciences, Vrije Universiteit, van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands. d.kistemaker@fbw.vu.nl
Journal of Neurophysiology
|January 27, 2006
Summary
Fast single-joint movements can be achieved without inverse dynamics calculations using an intermittent hybrid equilibrium point (EP) controller. This approach requires a detailed muscle model, challenging previous assumptions about EP control simplicity.
Area of Science:
- Biomechanics
- Robotics
- Neuroscience
Background:
- Equilibrium point (EP) controllers offer computational advantages by avoiding inverse dynamics calculations for movement control.
- Previous EP controller models inadequately represented muscle properties, limiting their ability to control fast movements.
- It has been debated whether EP controllers can achieve fast single-joint movements.
Purpose of the Study:
- To evaluate the capability of different EP controllers in reproducing fast human elbow-joint movements.
- To test EP controllers using a realistic musculoskeletal arm model.
- To determine if fast movements can be achieved without explicitly solving the inverse dynamics problem.
Main Methods:
- Measured fast elbow-joint movements in human subjects.
- Utilized a realistic musculoskeletal model of the human arm.
- Evaluated three EP controller types (open-loop alpha, closed-loop lambda, hybrid) in both continuous and intermittent versions.
Main Results:
- Only the intermittent hybrid EP controller successfully reproduced the speed of human movements.
- Accurate reproduction of fast movements necessitated a detailed representation of static muscle properties.
- The study demonstrated that fast single-joint movements are possible without explicit inverse dynamics computation.
Conclusions:
- Fast single-joint movements can be realized using an intermittent hybrid EP controller.
- Realistic muscle properties are crucial for effective EP control of rapid movements.
- Achieving fast movements with EP controllers is feasible but more complex than initially proposed.
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