Articulated robot


Industrial robots take a prominent part in the European production industry. However, the development of these robots is lagging behind the development of the production process. This has encouraged the University of Twente to research an improved control method for industrial robots to enable a more flexible application in the industry and a higher efficiency in production planning. Since this development is of such revolutionary nature, it cannot be tested on existing robots. This presents the need for a fully functional scale model of an industrial robot, which is the aim of this project.

The result is a scale model of an industrial robot, which complies with the aesthetic and kinematic characteristics of an articulated robot. Based on the kinematic structure various types of industrial robots can be distinguished with each their advantages. The articulated robot is most commonly applied in industry and its visual and technical characteristics are suited to be translated to a scale model. The figure below represents the kinematic structure of the developed robot arm, which aligns with the typical features of an articulated robot. This model represents the kinematic chain of the robot, which is used to derive the kinematic equations for controlling the robot's movement.

The robot arm utilises five links, which are serially connected by four rotational joints whose motion can be controlled. Rotational joints can be well protected against dirt and allow a flexible control and manoeuvrability of the manipulator. The serial arm is fixed at point A and serves to position the endpoint F in three-dimensional space.

The structural design of the robot arm has been developed to support the functional requirements. The client required the product to be developed for small scale production within a tight budget. Therefore, the components have been designed to comply with conventional rapid prototyping techniques, which are flexible and based on CAD data. The designed construction is a result of an iterative study to find an optimum between weight and stiffness. The construction is designed to withstand the mechanical loads of a milling application while maintaining high accuracy. With these features the product can support the development of the method and tools to improve the application of industrial robots in the renewed production environment. The datasheet below specifies the technical characteristics of the structural design.

Arm length Total length 500mm
Arm 1 250mm
Arm 2 250mm
Maximum reach 750mm
Maximum speed Axis 1 500 °/sec
Axis 2 333 °/sec
Axis 3 375 °/sec
Axis 5 461 °/sec
Total weight 1.65 kg
Maximum payload 0.25 kg
Weight/payload ratio 6.6 : 1
Accuracy ±0.3mm
Controller Arduino Mega 2560