Simulation and Evaluation of the Stair-Climbing Mechanism System of Powered Wheelchair
|關鍵字:||電動輪椅;輪椅;零矩點;機構設計;跨爬台階;Powered Wheel-Chair;Wheel-Chair;ZMP;Mechanism design;Stair-Climbing|
The research focuses on the design processes of the powered wheelchair (PWC) mechanism for climbing high stepped obstacles. Simulation and experiments are enrolled to evaluate the proposed mechanism system. The proportion of the elder people in the global population is getting higher. There are not enough social welfare facilities (e.g. ” Barrier-Free Space”) in most of the country currently. Even that driving the power wheelchair climbing or descending the stepped obstacles, it was a hard work for them. Based on the demand, there are a lot of studies and discussions about the assisting devices carrying goods and patients climbing over a step obstacle. For examples, there are many designing project regarding the mechanism of a jack, a track, an assembly wheel, a slider/rail and a slider-crank mechanism, etc. The main points are how to accomplish an entire motion, moreover, support loading to lift and carry it forward. Though the example of a jack and a slider/rail devices are easy to lift, but it need extra power resources. The track, the assembly wheel or slider-crank apparatus are assisting well to climb, but structures of those devices are too complicated. After evaluating several critical design factors, the Robot of Mars exploration Rover Mission in NASA was chosen as a reference model, and integrated with the parts of existing PWC to form a new climbing PWC model. This research proposed the mechanism which adopting some former experiences to form the linkage-type auxiliary mechanism for climbing stepped obstacles in CIDM laboratory(NC_pwc_06). In current study, the NC_pwc_06 mechansim system was discussed and redesigned and keep simple and lightweight as a design principle. By selecting the existing data and patents for climbing PWC, we analyzed and compared its advantages and drawbacks. The simple model has been theoretically derivated and simulated. In order to getting more complex, enormous and real model data, we chose MSC.ADAMS as the tool. It could be analyzed and validated at the related kinematic and dynamic models. To use the parametric analyzed module in ADAMS, and we did the optimization on the mechanical size. At last we had completed a set of basic procedure which develop PWC mechanism for stair-climbing. For searching for the optimal parameters of the PWC on stair-climbing, we applied former parametric analysis, generalized principles and experimental testing for better climbing performance. Furthermore, the design method which applied ZMP theory for providing the PWC stability criterion. We analyzed and tested each affected parameter for proposed climbing mechanism, and also further to improve them and generalize the results from them. Adopting the ZMP stable criterion for evaluating the stability of the PWC climbing mechanism. The parametic analysis and dynamic simulation of a propsed step-climbing PWC in the current study have been evaluated by a series of experimental testing, and the evaluating results have demonstrated that the propsed methodology was a practical and deserved to be a preliminary design and evaluating tool for step-climbing power wheelchair.