Candidate: Kevin Gerold Westermann
Title: Motor Control For Jumping To A Target
Date: November 30, 2018
Time: 3:00 pm
Place: E5 5047
Supervisor(s): Kulic, Dana
Abstract:
Investigating how humans perform dynamic movements is important for applications such as movement rehabilitation, sports training, and humanoid robot design and control. This thesis develops a methodology for analyzing dynamic movements, determining what factors are crucial to task success, and understanding the motor learning process. The approach is validated on the “jumping to a target” movement.
Qualitative analysis of jumping motion trajectories suggests a strong relation between the jumper’s center of mass (CoM) velocity at takeoff and the success of the jump. The takeoff velocity angle and magnitude must be matched to generate an appropriate ballistic trajectory to reach the desired target. If the takeoff velocity is inaccurate, the jumper can use their foot placement timing to correct the inaccuracy to a certain extent. Novice jumpers generally demonstrated more consistent CoM takeoff velocities as they performed more jumps. More experienced jumpers were observed to use foot placement timing more effectively, having higher rates of jumping success even when their CoM takeoff velocity was more variable than some novice jumpers.
Inverse optimal control was used to estimate what kinematic and dynamic tasks jumpers optimize throughout the movement. Direct optimal control was used to validate the recovered cost term weights. Repeatable patterns of cost term weights were recovered for jumps from all participants. Specific variations to the general pattern were observed for different jump target distances, participants with different jumping techniques, and unsuccessful jumps.
In both the qualitative trajectory analysis and inverse optimal control results, repeatable trajectory and motor control patterns were identified and correlated with specific jumping behavior, such as jump success, target distance, and motor learning effects.
This analysis framework can be extended to analyzing jumping motions in varied environment conditions, or be used to define the motor control methods of other dynamic human motions.