Design and Development of a Test Rig for Ergonomic Evaluation of Pistol grip Power Tools

DC手动工具通常用于制造业中紧固紧固件。这些手动工具将由于扭矩积累而在手上产生反作用扭矩。这导致操作手动工具的手用力。在这种重复性的任务中，手腕肌腱的重复拉伸导致其一些纤维被撕裂。这会导致肌腱发炎，导致肌腱炎。慢性肌腱疾病，如肌腱炎，是制造业中失去工作和工人赔偿的主要原因。然而，操作参数（如操作员位置、夹持力、拧紧算法和施加到所产生的反作用扭矩的扭矩）之间的相关性是未知的。我们提出了一种结合建模和实验的方法来研究影响反作用扭矩的因素，其目的是最大限度地减少手柄位移时，手枪握手工具被用来拧紧紧固件在各种操作位置。一阶线性模型，由弹簧和阻尼器将被用来代表人手。20名经验丰富的手动工具操作员将在不同位置使用特制框架上的仪表手枪式手动工具进行紧固任务。模型参数如弹簧刚度和阻尼系数将通过实验确定一个定制的测试台将被设计和建造，以模拟手工具的相互作用。该试验台将能够模拟各种弹簧和阻尼系数，这些系数是通过实验发现的。该试验台将用于研究各种操作参数和非操作参数（如性别）对反作用扭矩引起的手柄位移的影响。然后将确定使每个操作位置中的手柄位移最小化的参数组合。 使用研究结果，可以确定将导致每个操作位置的最小手柄位移的参数。这将有助于工业合作伙伴设计任务和工作场所，以减少重复性劳损，并遵循安全的工作习惯。

DC Hand tools are commonly used in manufacturing industries for tightening of fasteners. These hand tools will result in reaction torque on the hand due torque buildup. This results in forceful exertion of the hand operating the hand tools. Repeated stretching of tendons of the wrist during such repetitive tasks results in some of its fibers being torn. This results in inflammation of the tendon leading to tendinitis. Chronic tendon disorders, such as tendinitis, are major causes of lost work and workers' compensation in manufacturing industries. However, the correlation between operational parameters such as operator position, gripping force, tightening algorithm and torque applied to the reaction torque produced is unknown. We propose a combined modelling and experimental approach to study the factors that affect the reaction torque with the aim of minimizing the handle displacement when pistol grip hand tools are used to tighten fasteners in various operating positions. A first order linear model that consists of spring and dashpot will be used to represent the human hand. Twenty experienced hand tool operators will be conducting fastening tasks, in various positions, using instrumented pistol-grip hand tool on a specially made frame. The model parameters such as spring stiffness and damping coefficients will be determined through experiments A custom test rig will be designed and built to simulate the hand-tool interaction. The test rig would have capability to simulate various spring and damping coefficients that are experimentally found. The rig will be used to study the effect of various operational parameters and non-operational parameters such as gender on handle displacement due to reaction torque. The combination of parameters that would minimize the handle displacement in each operational position will then be determined. Using the results of the research, one can determine the parameters that would result in minimal handle displacement for each operational position. This will help the industrial partner to design the task and workplace so that repetitive strain injuries are reduced and safe working habits are followed.