The potential for emulating the human footstrike using a Six Degrees-of-Freedom industrial robot
thesisposted on 15.04.2015, 10:23 authored by James A. Jones
Part of the testing process for athletic footwear is exposing the shoes to realistic wear conditions; this can be in the form of user trials or, as is becoming more common place, the use of mechanical test devices. However, current mechanical test devices tend to be somewhat simplistic and fail to expose the footwear to the realistic loading environment. Thus, the aim of this thesis was to investigate the potential of using an off the shelf 6 Degrees-of-Freedom industrial robot to emulate the ground contact phase of human gait. This was achieved through addressing four research questions. The first research question aimed to outline the biomechanical features that were to be emulated and what their typical values were. Kinematics and kinetics of the real human gait were then collected, for use in programming the robot and evaluating its outputted movements. This was complemented by a comprehensive review of relevant literature. Previous investigations had highlighted the need for understanding of the robot s capabilities. This was taken further and input parameters such as level of robotic smoothing, programme velocity and the number of three dimensional co-ordinate points used were found to have an effect on the output kinematics of the robot. These features were also found to be part of the accompanying programme software (RoboGuide). Despite this, the differences were not identical and it was concluded that the software could only have a limited use in supporting the wider thesis aim. Prior to emulation, there was a need for robot set-up and its environment to be optimised. A new robot end-effector, with improved biofidelity, was developed which incorporated a new way of generating the robot motion that intended to aid kinetic and kinematic emulation. Further to this, analysis on robot movements in various locations identified the optimal location for the ground contact phase to be achieved. Using all of the gathered knowledge the robot was programmed to complete a footstrike for human walking using two types of programming method. When the robot is programmed directly with the human kinematic data the emulation of the footstrike is relatively poor; ground contact time is too long with an increased footprint size and poor ground reaction force profiles replication. Using a rotation about a fixed point on the footform led to improved, although not complete, emulation of the human gait parameters. The developed system has been shown to improve on previous work at Loughborough University and is also comparable with what is being used in industry and developed within academia. The concept remains in the early phases but the current study indicates that future work can move the robot further towards being able to produce a more biofidelic emulation that can be used in the footwear testing industry.
- Mechanical, Electrical and Manufacturing Engineering