Assessing upper limb joint comfort and optimizing handheld controller operations

The prolonged operation of a handheld controller for unmanned equipment can pose the risk of work-related musculoskeletal disorders (WMSDs) to its operator. To enhance the comfort of upper limb joints during such operations, the digital human and task scenario model was established with the JACK ergonomic analysis software. Comfort assessment models of joint moments and angles were established respectively, and the relationship between upper limb joint comfort and different forward inclination angles of the atlanto-occipital joint was studied. A multi-objective function for optimizing the upper limb posture during handheld controller use was formulated. The non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ) with the elite strategy was introduced to solve the optimal upper limb posture, obtaining the optimal postures for handheld controller operations and designing supportive devices. Intuitionistic fuzzy numbers were then employed to handle the uncertainty and hesitation in a decision-maker's assessment of design solutions, selecting the optimal design for supportive devices used with the handheld controller in its optimal posture.