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Introduction. One of the tasks of two-link manipulators of industrial robots that move the end-effector along complex trajectories (e.g., robot welder) is associated with the need for careful programming of their movement. For these purposes, manual programming methods or training methods are used. These methods are quite labor-intensive, and they require highly qualified service personnel. A possible solution to the problem of programming the manipulator movements is the simulation of motion with the calculation of angular coordinates. This can help simplify the geometric adaptation of the manipulator in the process of debugging the control program.   Therefore, this work aimed at calculating coordinates for programming the control system of a two-link manipulator operating in an angular coordinate system and moving the end-effector along a complex trajectory (e. g., when welding car bodies).   Materials and Methods. A two-link robot manipulator designed for cyclically repeating actions in an angular coordinate system was considered. The manipulator consisted of two rotating links: “arm” and “elbow”, which were fixed on the base. The base could rotate, which provided a third degree of freedom. This configuration increased the working area of the manipulator and minimized the area for its placement in production. The movement of the manipulator end-effector could be performed if the kinematics provided its positioning along three Cartesian and three angular coordinates. For software control of robots, including welding robots operating in an angular coordinate system and performing the movement of the end-effector along a complex trajectory, it was required to calculate the angular coordinates of the movement of the end-effector of a two-link articulated manipulator. The robot control system should determine the position of the tool in the angular coordinate system, converting it for user friendliness into x, y and z coordinates of the Cartesian coordinate system.   Results. The relations of angular and Cartesian coordinates have been obtained. They can be used for calculating when programming the control system of a two-link manipulator of an industrial robot and organizing the exchange of information between the user and the control system, as well as for checking the accuracy and debugging the movement of the end-effector of an industrial robot through feedback.   Discussion and Conclusion. The presented results can be used for software control of a welding robot operating in an angular coordinate system and performing a complex trajectory of the end-effector of a two-link articulated manipulator (gripper). A manipulator operating in an angular coordinate system can be used for contact spot welding when moving the end-effector along a complex trajectory using a positioning or contouring control system. These systems control the movement of the end-effector along a given trajectory with the help of technological commands.

Introduction. The work objectives were the analysis and application of the technology of electrospark deposition of wear-resistant metal coatings on cutting tools or machine parts for their hardening or dimensional restoration.Materials and Methods. The technology, device and principle of operation of the modernized installation intended for electric spark application of wear-resistant metal coatings with composites T15K6, VK8 and VK6 are considered.Results. To determine the parameters of the upgraded electrospark alloying plant, experiments were carried out on hardening of polished samples made of steel 45 with hard alloy T15K6 with dimensions of 25×25×25 mm. As a result of using the experiment planning method, the possibility of selecting and adjusting the installation parameters was confirmed. The following parameters were selected for hardening samples made of steel 45 with hard alloy T15K6: current I = 1-2–A, voltage U = 40-75 V, capacitor bank capacity = 60–100 µF.Discussion and Conclusions. The use of carbon dioxide as a protective medium enables to increase the number of passes and, accordingly, the number of coating layers to twenty, to obtain a total thickness of up to 0.3 mm with a dense structure without oxides. Coatings of this thickness make it possible not only to strengthen, but also to restore the dimensions of worn machine parts. The parameters of the technological modes of electrospark alloying significantly affect the intensity of coating application and the quality of the resulting surface. A rise in the electrical parameters causes an increase in the intensity of each individual discharge and, within certain limits, contributes to an increase in the amount of the transferred coating material, as well as to deeper transformations of the coated surface in the discharge zone. Thus, an electrospark alloying plant equipped with monitoring and diagnostic tools, as well as with a protective gas supply system, can be used for hardening and restoring machine parts and cutting tools.

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