Study on the influence of joystick handle shape on manipulator control accuracy

Introduction. Manipulator control is widely used in operator-driven systems, including logging, construction equipment, and aircraft. To facilitate operator input into control systems for such machinery, joysticks or sidesticks—manipulated along two or three axes – are commonly employed. The design of these joysticks can vary significantly depending on the control task at hand. The shape of joystick handles may influence tactile feedback perception, mechanical force application, and overall feedback depth between the operator and the equipment. The aim of this study is to examine how different joystick handle shapes, sizes, and gripping methods affect the accuracy and speed of operator control. Methods and materials. To objectively measure joystick handle positioning accuracy and speed, a computer-based test was developed, displaying visual feedback on a monitor. A bootstrapping approach was used to assess statistically significant differences between groups. Cluster analysis and dimensionality reduction techniques, including Principal Component Analysis (PCA) and Uniform Manifold Approximation and Projection (UMAP), were applied alongside the k-means unsupervised machine learning method to identify potential clusters in the data. Results. Cluster analysis using PCA, UMAP, and k-means did not reveal distinct groups. However, weak clustering tendencies were observed in the UMAP representation. No statistically significant differences were found in joystick positioning accuracy across different handle shapes, sizes, and gripping methods. From a speed and accuracy perspective, variations in joystick handle shape, size, and grip do not significantly impact operator performance, provided the joystick handle maintains an ergonomic design. In tasks where speed is prioritized over precision – while maintaining acceptable accuracy – full-size joysticks with a palm grip are recommended.