Haptic devices allow a human to interact physically with a remote or virtual environment by providing tactile feedback to the user. In general haptic devices can be classified in two groups according to the energetic nature of their actuators. Devices using electric motors, pneumatic or hydraulic cylinders or other similar actuators that can add energy to the system are considered "active." Devices using brakes, clutches or other passive actuators are considered "passive" haptic devices. The research presented here focuses on the use of passive haptic devices used during teleoperation, the remote control of a "slave" device by the haptic "master" device. An actuation scheme as well as three different control methods is developed for providing the user with haptic feedback. As a final step, the effectiveness of the controllers is compared to that of a commercially available active haptic device. Twenty subjects provide data that shows the usefulness of the passive device in three typical teleoperation tasks.

In this study, a two axes linear positioning system for testing and applying different rapid prototyping techniques was designed and manufactured. A cable/ pulley mechanism is utilized in the system for transmitting motion from motors into linear motion. Use of a cable/ pulley mechanism overcomes the problems resulting from the utilization of conventional drive systems like ball screws and decreases the overall cost of the system. The carriage elements of both axes were designed and manufactured by using investment casting. The molds used in casting were also designed and manufactured within this study. The designed system is controlled by a servo motion control system composed of a motion controller, DC servo motors and linear encoders. All elements of the motion control system were selected, integrated and programmed within the scope of the study.

M. Tech. Electrical Engineering. / Discusses how to develop the kinematic and dynamic model and the controller for the 2-DOf motion platform used in an augmented reality environment for wheelchair driving. This comes as a motivation to help to train disabled and elderly people to drive wheelchairs.. With accurate inverse dynamic model, it is possible to achieve high performance control algorithms of robots and direct dynamic model is required for their simulation. The other part of this research was to model and control the roller for the feedback of the wheelchair wheels.

Cranes are widely used in material-handling and transportation applications, e.g. in shipyards, construction sites, and warehouses. As they are critical to the economic vitality of modern-day industries, improving crane performance and ease of use are important contributors to industrial productivity, low production costs, and workplace safety. In a typical crane operation, a payload is lifted, moved to its destination, and then lowered into place. This dissertation aims to improve crane performance and reduce task difficulty for the human operator in the movements mentioned above, namely: 1) Moving payloads laterally in the horizontal plane, 2) Lifting payloads off the ground, and 3) Lowering or laying down payloads on the ground. The design of a novel and intuitive human-machine control interface is the focus for improving operations that involve moving payloads laterally. The interface allows operators to drive a crane by simply moving a hand-held device through the desired path. The position of the device, which is tracked by sensors, is used to generate command signals to drive the crane. This command is then input-shaped such that payload oscillations are greatly reduced, making it much easier for the operator to drive the crane. Several facets of this crane control method are examined, such as control structure and stability, usability contexts, modes of operation, and quantitative measures (by means of human operator studies) of performance improvements over standard crane control interfaces. Lifting up a payload can be difficult for the operator, if the hoist is not properly centered above the payload. In these potentially dangerous and costly ``off-centered" lifts, the payload may slide on the ground and/or oscillate in the air after it is hoisted. Newtonian and Coulomb friction models that focus on the stiction-sliding-separation contact dynamics are derived and experimentally verified to study off-centered lifts. Then, with the goal of aiding operators during lift operations, simple but practical, self-centering solutions are proposed and implemented. Laying down or lowering a payload to the ground can also be challenging for operators in certain situations. For example, laying down a long, slender payload from a vertical orientation in the air, to a horizontal position on a flat surface. If the operator does not properly coordinate the motions of the crane in the vertical and horizontal directions simultaneously, then the potential hazards that may occur during these operations include: 1) slipping of the pivot about which the payload rotates, leading to sudden and dangerous payload movements; and 2) excessive hoist cable angles that lead to ``side-pull" problems. Newtonian and Coulomb friction models are derived to describe this lay-down scenario. The forces and motions experienced by the payload are then used to determine the motion trajectories that the crane and payload should follow to execute a successful lay-down maneuver. Finally, a special chapter is included to address the oscillation control of systems that have on-off nonlinear actuators, such as cranes powered by relay-controlled circuits. Due to their simplicity, ruggedness, and long service life, this type of crane can be commonly found in older factories or in applications where precise motion control is not a strict requirement. However, controlling payload oscillations on this type of crane is challenging for two reasons: 1) Relays that can only be turned on or off allow for only limited control over the crane velocity; and 2) These cranes typically have nonlinear asymmetrical acceleration and deceleration properties. Methods are derived for determining the relay switch-times that move single-pendulum and double-pendulum payloads with low residual oscillations.

In this thesis, a high precision motion and position control system has been developed and applied to a high voltage sphere gap control and measurement system. The system is able to support up to 3-axes position and motion control. The control system includes a microcontroller card, three DC servo motor driver cards and a data storage unit. To provide communication between computer and motion control system, the Universal Serial Bus (USB) port is used. The microcontroller card is equipped with an USB interface and a PIC (Peripheral Interface Controllers) microcontroller. This microcontroller controls the dedicated motion control processors (LM629), on servo motor driver cards and read/write operations of data storage unit, which consists of a Multi Media Card.

This thesis investigates the questions of where to grasp and how to grasp a given object with an articulated robotic grasping device. To this end, aspects of grasp synthesis and hand motion planning and control are investigated. Grasp synthesis is the process of determining a palm pose with respect to the target object, as well as a hand joint configuration and/or grasp contact points such that a successful grasp execution is allowed. Existing methods tackling the grasp synthesis problem can be categorized in analytical and empirical approaches. Analytical approaches are based on geometric, kinematic and/or dynamic formulations, whereas empirical methods aim at mimicking human strategies.An overarching idea throughout this thesis is to circumvent the curse of dimensionality, which is inherent in high-dimensional planning problems, by incorporating empirical data in analytical approaches. To this end, tools from the field of constrained optimization are used (i) to synthesize grasp families based on available prototype grasps, (ii) to incorporate heuristics capturing human grasp strategies in the grasp synthesis process and (iii) to encode demonstrated grasp motions in primitive motion controllers.The first contribution is related to the computation and analysis of grasp families which are represented as Independent Contact Regions (ICR) on a target object’s surface. To this end, the well-known concept of the Grasp Wrench Space for a single grasp is extended to be applicable for a set of grasps. Applications of ICR include grasp qualification by capturing the robustness of a grasp to position inaccuracies and the visual guidance of a demonstrator in a teleoperating scenario. In the second main contribution of this thesis, it is shown how to reduce the grasp solution space during the synthesis process by accounting for human approach strategies. This is achieved by imposing appropriate constraints to a corresponding optimization problem. A third contribution in this dissertation is made to reactive motion planning. Here, primitive controllers are synthesized by estimating the free parameters of corresponding dynamical systems from multiple demonstrated trajectories. The approach is evaluated on an anthropomorphic robot hand/arm platform. Also, an extension to a Model Predictive Control (MPC) scheme is presented which allows to incorporate state constraints for auxiliary tasks such as obstacle avoidance.

Motion planning is central to the efficient operation and autonomy of robots in the industry. Generally, motion planning of industrial robots is treated in a two-step approach. First, a geometric path between the start and goal position is planned where the objective is to achieve as short path as possible together with avoiding obstacles. Alternatively, a pre-defined geometric path is provided by the end user. Second, the velocity profile along the geometric path is calculated accounting for system dynamics together with other constraints. This approach is computationally efficient, but yield sub-optimal solutions as the system dynamics is not considered in the first step when the geometric path is planned. In this thesis, an alternative to the two-step approach is investigated and a trajectory planner is designed and implemented which plans both the geometric path and the velocity profile simultaneously. The motion planning problem is formulated as an optimal control problem, which is solved by a direct collocation method where the trajectory is parametrised by splines, and the spline nodes and knots are used as optimization variables. The implemented trajectory planner is evaluated in simulations, where the planner is applied to a simple planar elbow robot and ABB's SCARA robot IRB 910SC. Trade-off between computation time and optimality is identified and the results indicate that the trajectory planner yields satisfactory solutions. On the other hand, the simulations indicate that it is not possible to apply the proposed method on a real robot in real-time applications without significant modifications in the implementation to decrease the computation time.

Motion controlled games can be a good physical activity for children, but the game has to be fun and engaging. We have, with a starting point in an existing base game, developed an achievement module which follows certain code standards to make it easier to understand, and to make hand overs of the code smoother. More work on the rest of the game has also been done to make it more engaging, while clean up of the existing code to follow the same standards.

People call the year of 2016 as the year of virtual reality. As the world leading tech giants are releasing their own Virtual Reality (VR) products, the technology of VR has been more available than ever for the mass market now. However, the fact that the technology becomes cheaper and by that reaches a mass-market, does not in itself imply that long-standing usability issues with VR have been addressed. Problems regarding motion sickness (MS) and motion control (MC) has been two of the most important obstacles for VR technology in the past. The main research question of this study is: “Are there persistent universal access issues with VR related to motion control and motion sickness?” In this study a mixed method approach has been utilized for finding more answers related to these two important aspects. A literature review in the area of VR, MS and MC was followed by a quantitative controlled study and a qualitative evaluation. 32 participants were carefully selected for this study, they were divided into different groups and the quantitative data collected from them were processed and analyzed by using statistical test. An interview was also carried out with all of the participants of this study in order to gather more details about the usability of the motion controllers used in this study. The results of this study has validated several existing frameworks for VR. And in conclusion, this study has also shown that both previous motion sickness experiences and gender factors weren’t significant in terms of general accessibility issues on PCVR platforms. There are hints showing that the VR technology on PC platform could be universal accessible, since both of the quantitative and qualitative results has provided some evidences supporting this finding. However, more similar studies need to be carried out in order to identify more possible factors that would give an impact on user experiences in VR. The results of this study has also given implications of that today’s VR technology is developing on the right track and it could slowly become adopted by the mainstream and mass-market in the future.

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