Research on the Collaborative Algorithm for Minimizing the Push-Pull Force of Multi-Condition Trolley Cases

With the increase in the frequency of modern people's travel, convenience and efficiency have become important indicators for evaluating the design and usage of suitcases. How to complete the push-pull operation of the suitcase at the low-est cost has become a typical problem in engineering optimization and ergo-nomics research. Based on four push-pull methods on a horizontal road surface, this paper first constructs a two-dimensional force analysis model of the suit-case, considering key factors such as the direction Angle and application point of friction force, gravity, etc. To scientifically evaluate the effects of the four methods, this paper adopts the Improved Particle Swarm Optimization Algo-rithm (IPSO) to find the minimum total push-pull force corresponding to each of the four methods. The results show that slightly inclined pulling has the best force efficiency in most cases, and the advantage is more significant when the friction coefficient is small. The force direction optimization problem is extended to the situation where the direction of the pull rod is variable. During the solution process, the Mul-ti-objective Optimization Framework (MOO) was introduced. Taking "minimum force" and "feasibility of operation Angle" as the trade-off objectives, and adopting the hybrid strategy of the Nelder-Mead simplex method combined with the particle swarm optimization algorithm, the efficient search for the push-pull direction Angle was achieved. Finally, the optimal direction that minimizes the energy expenditure of the human box system under the given ground conditions was determined, which has strong ergonomic adaptability and operational fea-sibility. Then, the focus is on studying the influence mechanism of the change in the length of the pull rod on the applied force. Under the condition of maintain-ing the push-pull Angle unchanged, systematically analyze the effects of differ-ent pull rod lengths on the force distribution and the overall push-pull force. The results show that increasing the length of the pull rod within a certain range can effectively reduce force consumption, but there is a critical point. Beyond this length, the marginal effect weakens significantly. This paper expands the scope of analysis to multi-parameter optimization problems in inclined road surface environments. Under this background, a multi-dimensional optimization model including three variables: ground tilt Angle, tie rod Angle and tie rod length is established.