Call2 Monitoring HYROPA

Public Summary Month 7/2012

Tue, 31 Jul 2012 08:05:04 GMT

The last projects phase comprises of finishing the experiment setup (Task 5), the experiment conducting and analysing (Task 6 and 7).

To enhance the usability and safety of the manual guiding of the robot a new input device was developed and implemented to the robot system. With this joystick a user-friendly guiding of the robot is possible. Inside the two handles of the joystick capacity sensors recognizes if the user has grasped the two handles with both hands. With the red button the user can then start the guided robot motion and with the green button the positions of the trajectory will be stored.

The joystick can be quickly mounted to the end-effector of the robot in different positions with a quick release skewer. This is necessary for an easy programming of the reconfiguration and of any individual handling task. The robot movement is realized by processing the data of the force-torques sensor induced by the user with the joystick.

Finally a complete reconfiguration task of the passive kinematics was successfully realized with the scenario of gripping different car exhausting pipes which will be presented in the final video.

Public Summary Month 5/2012

Wed, 13 Jun 2012 10:30:38 GMT

In the past reporting period a new force torque sensor with enhanced force range was integrated to the system. The gravity compensation and the error correction were then adapted to the new sensor properties (weight, size etc.). Finally the algorithm for the manual guiding of the robot with the sensor is realized. The user can easily grasp the tool and move it to the new position while the robot stores all positions in the program. This is a simple and user friendly procedure for teaching the reconfiguration and handling tasks with the robot.

Public Summary Month 3/2012

Mon, 02 Apr 2012 12:42:23 GMT

The first reconfiguration procedure of the passive gripping kinematic with force torque control was realized with the KUKA robot and the RSI interface: The inertial straight line path in y-direction of the robot could be automatically adapted to a force/torque controlled circular movement (see figure 1). The measured forces and torques of the experiment are diagrammed in the following figure 2. The algorithm for force compensation has been proved and works well.

Figure 1: test scenario with force controlled robot path

Figure 1: forces (left) and torques (right) during the controlled robot movement

The changing influence of the gravitational force of the passive arms is seen in the Y component of the measured forces and in the X component of the torque. There are some problems with the operating range of the force torque sensor: In some cases the reaction forces of the passive kinematic are higher than the maximum load force of the sensor. In the first step the grippers will be equipped with force absorbers to avoid force limitations during further tests. The second step is the exchange of the force torque sensor with a sensor with higher force range. The overall work progress of the experiment is without delays. Task 5 and 6 are currently in process.

Public Summary Month 1/2012

Tue, 31 Jan 2012 14:04:48 GMT

The work progress of the experiment is according to the work plan without any significant delays. The setup of the test arrangement (Task 5) is currently under construction. Therefore the passive arms are mounted at the clamping table and connected pneumatically and electrically. The layout and the gripper fingers are designed for the handling of 3D tubes.

The force-torque sensor is mounted to the robot together with the clamping device for the self-reconfiguration of the passive arms and also with some additional handling grippers. The sensor for the real-time manipulation of the robot path during reconfiguration was successfully installed and tested. For this testing the robot could be controlled with the sensor by using it as a manual guiding device.

The weights and centres of mass of all articulated components were determined and stored in a MATLAB routine to eliminate undesired mass effects of the sensor values. The next step will be the testing of the first simple reconfiguration procedure. Therefore the sensor guided reconfiguration algorithm will be implemented. The next report will present results and pictures of the first reconfiguration procedure.

Public Summary Month 11/2011

Mon, 12 Dec 2011 09:48:24 GMT

The completion of Deliverable DHyropa2 was aim of the last reporting period since September 2011 (Task 2). The IFF has therefore revised the passive gripping arms and the additional equipment (e.g. hydraulic system for clamping). The gripping arms were tested and adjusted to the maximal intended loads and forces of the validation scenario. The single components are now disposed for the following combination in the work cell.

The current work is related to the automatically path planning (Task 3) and the force compensation (Task 4). Parallel to this work the scenario setup “manipulation of 3D formed tubes” for the validation will be prepared using simulation (Task 5; figure 1). The arms are holding different tubes (e.g. car exhaust pipes) for applying manipulation tasks (e.g. flange welding, trimming, labelling). The most critical points for the validation tests are the necessary reachability and flexibility of the arms, which have to match with the scenario demands.

Figure 1: simulation of the test scenario

Public Summary Month 9/2011

Fri, 14 Oct 2011 11:33:44 GMT

The Fraunhofer IFF continued the work on Task 2 “Realisation of passive kinematics” and began working on task 3 “Revaluation of path planning”. The experiment will probably reach milestone M1 “realisation of passive kinematics” at the end of November also with providing the Deliverable DHyropa2 “Passive kinematics prototype”.

The flexible arms have been modified and reassembled to prepare the scenario validation in task 5 ”Setup of test arrangement”. The initial tension of the arms was adjusted to the intended handling weights and the hydraulic system (for locking and unlocking the arms) was upgraded to the required pressure, flow rates and strokes. The mounting on the robot cell will be the next step.

Based on the classification of the use cases the manipulating of 3D tubes will be selected to demonstrate the properties of the flexible robot system. Therefore the number of joints must be matching to the desired handling tasks. For the grasping of different 3D formed tubes the arms will be mounted directly at the clamping table. The robot will achieve the reconfiguration of the arms and the transport of the tubes. The task of the flexible arms is to fix the tubes in a defined position at the table for executing different manufacturing steps such as cutting/trimming, connecting, and marking/labelling with the tubes. Such tubes are typically used in the automotive industry for the piping of ventilation and air conditioning or braking and steering circuits. Future possible uses are the production and assembling of 3D tubes for connecting of fuel cells with peripherical devices.

Public Summary Month 7/2011

Fri, 19 Aug 2011 11:11:10 GMT

Project objectives

The experiment HYROPA demonstrates the possibility to reduce the technical effort for highly flexible robot cells using passive kinematics and state-of-the-art serial robotic arms. The core idea of the experiment is the application of state-of-the-art industrial robots together with fixable, passive kinematic arms, which have a large number of degrees of freedom, but without their own drives. Therefore the passive kinematic is formed of a combination of different revolute, linear or spherical joints. The joints are freely moveable and have no active drives. Each joint can be locked in an individual position with a locking mechanism. The position of each joint depends on the actual workpiece or work task. The locking mechanism can be implemented according to a mechanical, hydraulic or electrical principle.

Project status

The following tasks have been processed since the start of the project:

- Scenario description

- Design of the experiment formulas

- Concept of passive kinematics setup

- Commissioning and installation of the experiment equipment: industrial robot KUKA KR 16, KUKA Robot Sensor Interface and the Schunk Force-Torque Sensor

Several scenarios are described for difference handling tasks and branches. We have derived different cell setups from these scenarios (e.g. mounting place, number of passive arms and joints). The single kinematic tests will be performed with experiment formulas based on the user scenarios.

The technical drawings of the robot cell layout and the passive kinematic setup is the current output of task 2. The next steps are the realisation of the passive kinematic modules and the mounting on the robot cell.

The industrial robot could be installed at the facilities of the Fraunhofer IFF in Magdeburg. The KUKA Robot Sensor Interface (RSI) was installed at the robot controller and tested. The robot will be further equipped with the Force-Torque-Sensor via the RSI connection to compensate faulty gripping. A welding and clamping table is a part of the robot cell for mounting the passive kinematics and to perform different handling tasks.