HERMIES-III is an autonomous robot comprised of a seven degree-of-freedom (DOF) manipulator designed for human scale tasks, a laser range finder, a sonar array, an omnidirectional wheel-driven chassis, multiple cameras, and a dual computer system containing a 16-node hypercube expandable to 128 nodes. The current experimental program involves performance of human-scale tasks (e.g., valve manipulation, use of tools), integration of a dexterous manipulator and platform motion in geometrically complex environments, and effective use of multiple cooperating robots (HERMIES-IIB and HERMIES-III). The environment in which the robots operate has been designed to include multiple valves, pipes, meters, obstacles on the floor, valves occluded from view, and multiple paths of differing navigation complexity. The ongoing research program supports the development of autonomous capability for HERMIES-IIB and III to perform complex navigation and manipulation under time constraints, while dealing with imprecise sensory information.

A collision-free trajectory control for multiple robots is proposed. The proposed method is based on the concept of neural optimization network. The positions or configurations of robots are taken as the variables of the neural circuit, and the energy of network is determined by combining various functions, in which one function is to make each robot approach to its goal and another helps each robot from colliding with other robots or obstacles. Also a differential equation of the circuit which tends to minimize the energy is derived. A new method for describing collision between articulated arms is presented and some heuristic method to improve the feasibility and the safety of the trajectory is proposed. Also illustrative simulation results for mobile robots and articulated robot arms are presented.

A prototype robot for picking citrus is described which utilized real-time, color machine vision to vision-servo the robot on a targeted fruit. A programming technique is presented which simplified development of the task-level, robot control program. An economic evaluation of robotic harvesting in Florida determined that robotic harvesting would be approximately 50 percent more expensive than conventional hand harvesting. Harvest inefficiency was identified as the most influential factor affecting robotic harvesting economics. Field trial performance is summarized and the potential of commercial robotic harvesting discussed.

A parallel-processing system for locating parts and controlling an industrial robot is proposed. The system employs Transputers and Occam to achieve parallelism. In conjunction with a novel vibratory sensor, the system enables a robot to determine the exact location of parts which have been picked up from a semi-ordered work place. A new algorithm for obtaining the coordinates of the parts using the sensed vibration and deflection signals is described. The algorithm dispenses with the lengthy and complex equation-solving procedures previously required. Instead, it only involves looking up a data table and performing simple two-dimensional interpolation calculations. The design of the algorithm to ensure efficient parallel operation is described. Experimental results showing the successful implementation of the algorithm on the proposed system are presented.

The problem of path planning for a mobile robot has been studied extensively in recent literature. Much of the work in this area is devoted to the study of path planning for an earth-bound robot in two dimensions. In this paper, we explore the problem for a robot that can fly in three dimensional space or crawl on 3D surfaces or use a combination of both. We assume that the obstacles can be modeled as polyhedral objects.

The heavy reliance which New Zealand places on its primary industries makes it important that every effort be made to automate these industries to improve their productivity. This presents many unique problems, especially when consideration is given to the use of robots in the horticultural sector for the handling of soft fruit for export. As part of this process, fruit must be individually packed in trays without the risk of damage. This is currently achieved through labour-intensive manual handling and for this reason a range of specialised robot grippers have been developed. These, to varying degrees, overcome many of the problems associated with the harsh handling which occurs when conventional industrial robot grippers are used.

The global trajectory control of walking machines is addressed here with particular attention paid to the consequences of actuator redundancy for control and to the inclusion of actuator dynamics in trajectory controller design. Redundancy of actuation, typical of walking machines, results in the trajectory control problem being formulated perforce in a global coordinate frame, instead of the joint space, as in nonredundant manipulators. This lack of one-to-one correspondence between the degrees of freedom of motion in the global coordinate frame and the actuators results in coupling between the different trajectory control loops. A mechanism for reducing this coupling effect is proposed here, along with a procedure to take into account approximately the effect of actuator dynamics in designing the trajectory controllers. The proposed methods are evaluated by simulation for an example problem in legged locomotion and are shown to be effective.

The DELTA parallel robot, designed by an EPFL (Ecole Polytechnique Fédérale de Lausanne) research team, is a mechanical structure which has the advantage of parallel robots and ease of serial robots modeling. This paper presents solutions for a complete modeling of the DELTA parallel robot (direct and inverse kinematics, inverse statics, inverse dynamics), with few arithmetic and trigonometric operations. Our method is based on a satisfactory choice of kinematic parameters and on a few restricting hypotheses for the static and dynamic models. We give some details of each model, we present some computation results and we put the emphasis on some particular points, showing the capabilities of this mechanical structure.

This paper presents the findings of a research programme leading to the development of a robotic system for packaging poultry portions. The results show that an integrated system, incorporating machine vision and robots, can be made feasible for industrial use. The elements of this system, including the end-effector, the vision module, the robot hardware and the system software are presented. Models and algorithms for automatic recognition and handling of poultry portions are discussed.

Robots will require some form of proximity sensing in order to perform many delicate exploration, assembly and manipulation tasks. This paper describes a novel articulated tactile probe which can locate and accurately measure the 3-dimensional surface contours of small objects. Although lacking the speed of data acquisition possible with vision and other non-contact sensors, the resulting data is easily processed to give useful information about an object.

A fundamental study on the control of hydraulically actuated robots is presented. Dynamic modelling is performed in both time-domain and frequency-domain. It is shown that the inclusion of hydraulic elements increases the order of the system. Hydraulic compliance is the most effective factor in this regard.

Three distinct control strategies are applied. Their performances are evaluated and compared. All three methods are exemplified with a two link hydraulic robot in a computer simulation. The robot has the same hydraulic configuration as many existing industrial manipulators. The simulation program is written in ACSL (Advanced Continuous Simulation Language) running on a VAX 11/750.

When a free-ranging walking machine carries its own fuel and power source as well as a payload, it is important to maintain high mechanical efficiency. If the masses of the legs are negligible then, in a straight and level walk, the only power to be generated would be that needed to overcome ground and wind resistance and internal frictions. The paper shows this to be the case when one-input straight-line generating mechanisms are used. However, when two-input mechanisms are used the actuators can work against each other resulting in finite, sometimes large, power requirements. The paper determines the effects of limb lengths and ground clearance on step length and quantifies the power requirements of serial-operated and parallel-operated legs. It shows that parallel-operation offers greater efficiency.

Prawns are a significant marine resource in Australia and elsewhere, but their processing after the harvest is a very labour-intensive operation. Every prawn is presently hand packed. The possibility of utilising machine vision and robots to automate this operation has been investigated. Experiments indicate that machine vision can classify prawns into mass-related categories better than people now do, and that prawn orientation can be determined by this means. Although at the present state of technology it appears infeasible for robots to make up the multi-layer fixed-weight packs of prawns as is now done manually, a change to single-layer variable-weight packs should allow this process to be automated and would offer significant advantages to the Australian industry.

The payload capacity of a conventional robot is usually limited as compared to the mass of the robot body. This is because a payload adds additional gravity loadings to the robot joints resulting in large input joint torques. To reduce the required input joint torques, the authors have proposed a mechanical balancing mechanism. Basically, the mechanism was designed to exactly balance the first three links of an articulated robot by adjusting the positions of counter-balancing masses so as to eliminate the gravity loading terms. Since the input joint torques are greatly reduced by adopting balancing mechanisms, a balanced robot is expected to carry heavier payload and move with higher speed and acceleration. This paper further investigates the possibilities of improving the payload capacity as well as speed and acceleration capabilities. These features were investigated under various operating conditions involving payload, maximum angular velocity, and acceleration period. Based upon the simulation results, the performances of the balanced robot are compared in detail with those of a unbalanced conventional robot.

A new type of an iterative learning control method is proposed for dynamic systems with uncertain parameters. The method, which employs the model algorithmic control concept in the iteration sequence, is shown to be convergent for linear time-varying systems. Then the method is shown to be applicable for continuous-path control of a robot manipulator.

The application of heavy robots is usually restricted to those problems where large loads are carried and high speed is not required. This paper proposes a method for the improvement of robot dynamic capabilities thus enabling a heavy robot to perform the fast manipulation. The approach follows the idea of “distributed positioning” and introduces redundancy. The concept adopted is proved on two different configurations: an elbow-scheme manipulation robot and a gantry welding robot.