Krzysztof Mianowski

Mechatronic design of open-structure multi-robot controllers

Abstract The paper proposes a structure for open, hierarchical, multi-device controllers. The proposed structure takes into account that the system may contain several robots of different types, a certain number of cooperating devices, diverse sensors and also the fact that the task, the system has to execute, and the number and type of its components may vary considerably over time. The concept has been verified by designing a controller for a prototype Robot of a New Type (RNT) robot. The flexibility of the system is due to the software, so the programming aspect is treated comprehensively in the paper.

A prototype robot for polishing and milling large objects

The paper describes a prototype robot which due to its serial‐parallel structure exhibits, high stiffness and has a large work envelope. These features make this robot suitable for relatively high precision machining operations on large workpieces. The conroller for this robot was based on MRROC++, which is a robot programming framework. Thus the controller could be tailored to the tasks at hand, including the capability of in‐program switching of kinematic model parameters. To obtain those parameters for different locations in the work‐space a calibration procedure using linear measurement guides has been devised.

The Mechatronic Design of a Human-like Robot Head

In this paper the design concept as well as the constructed human-like robot head is introduced. Main goal of the head design is the support of an adequate human machine interaction. Therefore, our robots head should be able to support non-verbally communication based on facial expressions but should also have the skills to observe the intention of a human operator. Based on experience done with a graphical simulation system, the artificial skin movement is examined to express specific facial expressions. These results lead to the basic for the mechanical head design. In the paper also the neck design and the new eye construction is presented. At the end of the paper the sensor system and the control architecture of the head is introduced.

Mechatronics of the Humanoid Robot {ROMAN}

Recent developments in the area of service robotics show an increasing interest in personal robots. Those personal robots can help to handle daily work and to entertain people. Both tasks require a robot that is able to communicate with people in a natural way. For these tasks non-verbal motions like gestures, mimic, and body pose are more and more important. Several anthropomorphic robots like [1], [6], [8], and [7] have been build in recent years. Although several goals could be reached humanoid robots are not able to communicate with humans in a natural way.

Designing Arms and Hands for the Humanoid Robot {ROMAN}

The interest in assistance and personal robots is constantly growing. Therefore robots need new, sophisticated interaction abilities. Psychologists point out that most of the human-human interaction is conducted nonverbally. For that reason, researchers try to enable humanoid robots to realize nonverbal communication signals. This paper presents a compact, lightweight, and low-cost arm and hand design to enable humanoid robots to use gestures as nonverbal interaction signals.

Development of the Design of Polycrank Manipulator Without Joint Limits

Some new results concerned with the design of POLYCRANK manipulators without joint limits are presented. Main features of such a solution are links in the form of light hollow cranks connected one to the other by cross-roller bearings. The first pre-prototype of POLYCRANK with six DOF’s has been completed and tested. Three first DOF’s, with parallel vertical axes are driven by electric Direct Drive units mounted coaxial in the base of the manipulator. Three last DOF’s are driven by light motors with gears mounted on the last link of the horizontal chain with using parallelograms. High speed of cyclic gross motion in the convex workspace and good isotropic properties are the main advantages of this manipulator. Proper choosing of such mechanical properties like high natural frequency with good damping of vibrations, high stiffness, relatively low Lost Motion, is the basic requirement and it was the main purpose of investigations. Main disadvantages of the previous version are high cost of DD motors and of big diameter cross-roller bearings. A new one version with much more less cost is consider. One of the basic features of it’s is a new serial-parallel modular arrangement of the arm and untypical spherical wrist.

Application of the RNT Robot to Milling and Polishing

A new type of robot with six DOF invented by K. Nazarczuk and K. Mianowski (1992) is presented in the paper. The robot arm has serial-parallel structure, high stiffness — comparable to that of parallel manipulators and very large workspace — comparable to that of serial robots. Lately the RNT robot has been adapted to milling of soft materials and polishing large surfaces. The controller of the robot is based on the MRROC++ library/language described by Zielinski at all. (1997, 1998, 1999). Due to the modularity of the software and its open structure, it is especially well suited to investigative tasks. It enables easy incorporation of any sensors. The information gathered by sensors can be used for on-line trajectory generation, monitoring the progress of machining or for subsequent analysis of results. The MRROC++ control system can generate any trajectories, and for the purpose of machining it interprets APT program CL-files produced by a UNIGRAPHICS CAD system. The power of the controller lies in the possibility of combining the off-line generated trajectory coded in APT with sensor-gathered information to generate an on-line resultant trajectory. The RNT robot has very good position repeatability (±0.02mm). For achieving good absolute accuracy a special procedure of local kinematic model correction has been developed and implemented. Large workspace and high manoeuvrability of the RNT robot enables it to machine work-pieces that no NC-machine can produce - any 3D surfaces can be obtained. The robot has successfully polished large metal surfaces and milled soft materials, e.g. wood and plastic.

RRLAB SEA — A highly integrated compliant actuator with minimised reflected inertia

The Robotics Research Lab (RRLab) is currently striving to bring the Bio-inspired Behaviour-Based Bipedal Locomotion Control (B4LC) to a physical platform. Regarding the actuation, dynamic walking poses specific requirements like impact tolerance and high acceleration capabilities. A linear Series Elastic Actuator (Sea) which is designed to meet the requirements is presented. A design approach to the drivetrain which is taking the reflected motor inertia into account, is depicted in order to achieve a high acceleration capability. The resulting Sea implementation features a drivetrain based on a high pitch ball screw as a single gear reduction. This positively impacts the efficiency, the backdrivability and most importantly reduces the reflected motor inertia. Furthermore, the design features a high degree of integration to achieve a high torque density and allow for a compact integration. To exploit its full potential, the actuator is encapsulated by a dedicated FPGA-based embedded system. In open-loop experiments all unlumped dynamic quantities of the actuator are identified.

Wheeeler – Hypermobile Robot

We have designed and built the prototype of hyper redundant, articulated mobile robot propelled on wheels and therefore called - Wheeeler. In this paper we present progress in our project, focusing on modeling and prototyping phase. We show model of the robot built and verified in 3D simulator and proof-of-concept 3-segment device. Wheeeler is designed to operate in a rough terrain and fulfill tasks such as climbing up or down the stairs, going through trenches, avoiding or climbing over obstacles, operating in narrow, limited spaces like ventilation shafts. The major difficulty of control of hypermobile robots is synchronization of multiple actuators. Design of the high level control system, which can help human operator to intuitively steer this robot is the main goal of our project. In the further part of this paper we introduce communication and control architecture.

End-Effector Sensors’ Role in Service Robots

Service robots, unlike their industrial counterparts, operate in unstructured environments and in close cooperation with human beings [3]. Thus, service robots must rely heavily on sensing and reasoning, while industrial robots rely mainly on precision of movement in a well-known and structured environment.