INCREASING THE RIGIDITY OF THE SELF-CENTERING DEVICES OF LATHES

Increasing the rigidity of universal self-centering devices is one of the topical trends in the design of machine tooling. Calculation of the load distribution between the turns and teeth of a spiral rack and pinion mechanism is a complex engineering problem. When working on the article, it was revealed that an adjacent pair of turns and teeth that are in engagement does not always coincide with a geometrical adjacent pair due to the error in the execution of turns and teeth along the pitch and profile. This is based on experimental data and the proposition that errors in the pitch and profile of the spiral determine the nature of the working pressures in the engagement of the turns and teeth. The article discusses technical solutions in which the rigidity of self-centering devices increases without significant structural changes due to the establishment of the correspondence of the algorithm for changing the elastic properties of parts of the spiral-rack mechanism to the algorithm for changing the load between the bearing elements. Constructive solutions based on the implementation of elastic displacement of the first most loaded turn are proposed, which allows to reduce the interference between the tooth of the cam rack and the turn of the disk spiral. This circumstance contributes to the redistribution of the load in the engagement of the bearing elements of the spiral-rack mechanism. The tests of the developed structures were carried out, which gave positive results.

Eco-friendly innovation gripping systems actuated by pneumatic muscles

The paper focuses on the development of innovative, bionic, eco-friendly and light gripping systems. Within this broader context the paper presents and discusses four innovative constructive solutions for a gripping system mountable on an industrial robot, based on actuation by a linear pneumatic muscle and transmission of motion by gear and rack mechanism. The method underlying the development of these novel

Design and implementation of a variable stiffness actuator based on flexible gear rack mechanism

SUMMARYVariable stiffness can improve the capability of human–robot interacting. Based on the mechanism of a flexible rack and gear, a rotational joint actuator named vsaFGR is proposed to regulate the joint stiffness. The flexible gear rack can be regarded as a combination of a non-linear elastic element and a linear adjusting mechanism, providing benefits of compactness. The joint stiffness is in the range of 217–3527 N.m/rad, and it is inversely proportional to the 4th-order of the gear displacement, and nearly independent from the joint angular deflection, providing benefits of quick stiffness regulation in a short displacement of 20 mm. The gear displacement with respect to the flexible gear rack is perpendicular to the joint loading force, so the power required for stiffness regulating is as low as 14.4 W, providing benefits of energy saving. The working principles of vsaFGR are elaborated, followed by presentation on the mechanics model and the prototype. The high compactness, great stiffness range and low power cost of vsaFGR are proved by simulations and experiments.

Design of Variable Stiffness Actuator Based on Modified Gear–Rack Mechanism

Variable stiffness actuators (VSAs) can improve the robot's performance during interactions with human and uncertain environments. Based on the modified gear–rack mechanism, a VSA with a third-power stiffness profile is designed. The proposed mechanism, used to vary the joint stiffness, is placed between the output end and the joint speed reducer. Both the elastic element and the regulating mechanism are combined into the modified gear–rack (MGR), which is modeled as an elastic beam clamped at the middle position. Two pairs of spur gears are engaged with the rack and considered as the variable acting positions of supporting forces. The joint stiffness is inversely proportional to the third power of the gear displacement, independent from the joint position and the joint deflection angle. The gear displacement is perpendicular to the loading torque, so the power consumed by the stiffness-regulating action is low (14.4 W). The working principle and the mechanics model are illustrated, and then, the mechanical design is presented. The validity of the VSA is proved by simulations and experiments.

Design and Analyses to Determine the Minimum Acting Force of a Gripper for Handling the Parts with Robots

This paper presents a model of gripper designed for KUKA robot, together with a series of static and dynamic analyses for different loadings of it. Both the 3D design and static and dynamic analyses have been conducted using the design of Creo package with Parametric and Simulate the modules. The Gripper designed has in its composition a mechanism type rack-pinion type and a quadrilateral mechanism, for carrying out a parallel movement of jaw. It was determined the minimum force of actuation of the pinion-rack mechanism of gripper for maintaining the piece caught in gripper jaws, at the maximum speeds of rotation of the robot.

The Load Simulation Research of Nose Landing Gear Steering

The nose landing gear is a vital component of an aircraft,which has an important impact on the safety of the aircraft.This paper studies the system of nose landing gear steering on the basis of the gear and rack mechanism durability test of a certain type of civil aircraft landing gear steering. Furthermore,it puts forward a method of passive loading,which can simulate the friction when the nose landing gear reciprocating turning,and establishes the mathematical model. The simulation results show that the simulator can meet the requirements of load,and laid a theoretical foundation for the subsequent actual work.