This diploma thesis deals with design and implementation of the controllers of a mobile walking robot. The advantage of these controllers are their kinematics and geometrics independent representation, which allow to use them for different robot types and tasks. In this thesis the contact controller is designed, which minimizes residual forces and torques at the robot's center of gravity, and thereby stabilize robot's body. Next the thesis deals with a posture controller, which maximizes a heuristic posture measure to optimize posture of robot body. Because of this optimization, legs are moved away from their limits and therefore they have more working space for next move. Implementation of the chosen solution is made on the robot's MATLAB mathematical model. Controllers are composed into a control basis, that allows to solve general control tasks by simultaneous combination of contained controllers. The algorithm was created for that simultaneous activation and its operation was explained on flow charts.

Background: Older adults walk more slowly than healthy young adults at fast and normal walking speeds. These age-associated changes in mobility impact upon daily function. A slower gait, for example, may reduce the older adult’s ability to safely cross at traffic intersections due to the time restriction. Recent research has demonstrated whole body vibration (WBV) can improve the strength and power (Roelants, Delecluse & Verschueren, 2004; Russo et al., 2003; Verschueren, Roelants, Delecluse, Swinnen, Vanderschueren & Boonen, 2004) of community dwelling elderly females, and the mobility of nursing home residents (Bautmans, Van Hees, Lemper & Mets, 2005; Bruyere et al., 2005). To date, no published research has examined the impact WBV has on the gait parameters of community dwelling elderly females. The research was conducted in three phases. Phase One – Development of a WBV Platform: This phase outlines the development of a WBV platform (ACUWBV) that was designed and built for this research. A unique aspect of the ACUWBV was the method of adjusting WBV amplitude and therefore intensity. Current WBV technology, using tilting oscillations, requires the individual to increase their stance width. The ACUWBV allowed for the adjustment of WBV amplitude while maintaining the same stance width. The reliability and accuracy of the ACUWBV eccentric cam was measured during this phase of the research. Although an intraclass correlation coefficient of 0.4 was calculated and is considered an indication of low reliability, calculations of typical error (TE -95% error range) for each amplitude indicated the error to be small in the overall precision of the instrument. Specifically, at a frequency of 20 Hz, the expected WBV acceleration ranges for amplitudes of 0.5 mm and 1.0 mm were 7.58 m.s-2 to 8.85 m.s-2 (TE = 0.02 mm) and 16.90 m.s-2 to 17.53 m.s.-2 (TE = 0.01 mm), respectively. Phase Two – Pilot Study: This phase established the response of elderly community-dwelling female fast gait to WBV. Seven elderly female participants attended three WBV sessions per week for three weeks. Participants performed fast walks over an electronic walkway (GAITRite) at the end of each WBV session. A time-series graph displayed a linear increase in stride velocity over the three week intervention period. Conversely, stride time, stance time and double support time exhibited linear decreases. However, stride time (p=0.04) and stance time (p=0.04) were the only variables that exhibited a significant difference. It was concluded that the linear changes in stride velocity, stride time, stance time and double support time warranted further investigation with a larger sample size within a longer intervention period. Phase Three – Major Study: Phase three was an extension of phase two. This WBV intervention study was performed over a twelve week period. Twenty-two elderly female participants were placed in one of two groups. Group one (placebo/WBV; Group; n=12) was exposed to a placebo intervention for the first six weeks followed by a six week WBV intervention. Group two (Group WBV/placebo; n=10) was exposed to WBV for the first six weeks and a placebo intervention for the following six weeks. Group placebo/WBV exhibited no change in stride velocity during the placebo period, but a seven per cent increase during the six week WBV period (p=0.005). The changes in stride velocity coincided with increases in stride length (p=0.017), and reductions in stride time (p=0.007), stance time (p=0.001) and double support time (p=0.001). Group WBV/Placebo demonstrated stride velocity to increase by five per cent during the WBV period. Although the time-series graphs demonstrated improvements in stride velocity to be associated with decreases in stride time, stance time, and double support time, the changes failed to reach significance. Single support time and stride length showed no change over the WBV period. The improvements shown by group WBV/placebo from the first six weeks of WBV were maintained during the six week placebo (detraining) period. In summary, WBV was an effective intervention for enhancing the walking speed of community dwelling elderly female gait. This form of exercise may have positive outcomes on the daily function of elderly females, which in turn may improve their quality of life.

Thesis (M.S.)--University of Oregon, 2008. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 70-75). Also available online.

abstract: Cerebral palsy (CP) is a non-progressive neurologic disorder characterized by motor pathway damage prior to functional development. Damage to the central nervous system impairs motor functioning, including control of motor movement, loss of coordination, and loss of purposeful posture in individuals with cerebral palsy. This creates abnormal walking gait, impaired balance, and loss of muscle control. Current research shows positive results in studying the use of rhythmic music and walking gait for individuals with neurologic disorders. However, most research focuses on neurologic disorders acquired later in life, such as post-stroke patients and individuals with Parkinson's disease and traumatic brain injuries. The current study addresses the impact of rhythmic music on walking gait for an individual with cerebral palsy. Research addresses whether the use of rhythmic music impacts: (a) endurance (laps, distance traversed, and steps taken) (b) cadence (steps per minute), (c) velocity (distance over time), (d) emotional responsiveness (positive or negative affect), and (e) motivation. The current study is a single subject, mixed method design under randomized treatment conditions. The subject is a 25-year-old female diagnosed with spastic diplegic cerebral palsy. The subject participated in a five-week study, three times a week for one hour each session. Assessment was conducted during the first session. The following 14 sessions included gait training either under treatment (the use of recorded rhythmic music accompanied by audible drum beat) or control (no music) randomly assigned prior to the beginning of the study. Data were collected through video recordings, subject and researcher journals, and emotional responsiveness surveys. Data were analyzed for treatment versus control conditions. Analysis of both quantitative and qualitative data indicated that rhythmic music does impact walking gait for individuals with cerebral palsy. When compared to control conditions, the treatment conditions showed an increase in endurance, cadence, and velocity, and improvement in affect and motivation. / Dissertation/Thesis / M.M. Music Therapy 2011

The Ph.D. thesis is focused on using the reinforcement learning for four legged robot control. The main aim is to create an adaptive control system of the walking robot, which will be able to plan the walking gait through Q-learning algorithm. This aim is achieved using the design of the complex three layered architecture, which is based on the DEDS paradigm. The small set of elementary reactive behaviors forms the basis of proposed solution. The set of composite control laws is designed using simultaneous activations of these behaviors. Both types of controllers are able to operate on the plain terrain as well as on the rugged one. The model of all possible behaviors, that can be achieved using activations of mentioned controllers, is designed using an appropriate discretization of the continuous state space. This model is used by the Q-learning algorithm for finding the optimal strategies of robot control. The capabilities of the control unit are shown on solving three complex tasks: rotation of the robot, walking of the robot in the straight line and the walking on the inclined plane. These tasks are solved using the spatial dynamic simulations of the four legged robot with three degrees of freedom on each leg. Resulting walking gaits are evaluated using the quantitative standardized indicators. The video files, which show acting of elementary and composite controllers as well as the resulting walking gaits of the robot, are integral part of this thesis.

Thesis (Ph. D.)--Victoria University (Melbourne, Vic.), 2008. / Includes bibliographical references.

The Ph.D. thesis is focused on using the reinforcement learning for four legged robot control. The main aim is to create an adaptive control system of the walking robot, which will be able to plan the walking gait through Q-learning algorithm. This aim is achieved using the design of the complex three layered architecture, which is based on the DEDS paradigm. The small set of elementary reactive behaviors forms the basis of proposed solution. The set of composite control laws is designed using simultaneous activations of these behaviors. Both types of controllers are able to operate on the plain terrain as well as on the rugged one. The model of all possible behaviors, that can be achieved using activations of mentioned controllers, is designed using an appropriate discretization of the continuous state space. This model is used by the Q-learning algorithm for finding the optimal strategies of robot control. The capabilities of the control unit are shown on solving three complex tasks: rotation of the robot, walking of the robot in the straight line and the walking on the inclined plane. These tasks are solved using the spatial dynamic simulations of the four legged robot with three degrees of freedom on each leg. Resulting walking gaits are evaluated using the quantitative standardized indicators. The video files, which show acting of elementary and composite controllers as well as the resulting walking gaits of the robot, are integral part of this thesis.

In this thesis, the walking of a humanoid system is simulated applying an optimal predictive control algorithm. The simulation is built using Matlab and Simulink softwares. Four separate physical models are developed to represent the single support and the double support phases of a full gait cycle. The models are three dimensional and their properties are analogous to the human&rsquo / s. In this connection, the foot models in the double support phases include an additional joint which connects the toe to the foot. The kinematic relationships concerning the physical models are formulated recursively and the dynamic models are obtained using the Newton &ndash / Euler formulation. The computed torque method is utilized at the level of joints. In the double support phase, the redundancy problem is solved by the optimization of the actuating torques. The command accelerations required to control the gait are obtained by applying an optimal predictive control law. The introduced humanoid walker achieves a sustainable gait by tuning the optimization and prediction parameters. The control algorithm manages the tracking of the predefined walking pattern with easily realizable joint accelerations. The simulation is capable of producing all the reaction forces, reaction moments and the values of the other variables. During these computations, a three dimensional view of the humanoid walker is animated simultaneously. As a result of this study, a suitable simulation structure is obtained to test and improve the mechanical systems which perform bipedal locomotion. The modular nature of the simulation structure developed in this study allows testing the performance of alternative control laws as well.

Human-robot interaction (HRI) is the study of how we as humans interact and communicate with robots and one of its subfields is working on how we can improve the collaboration between humans and robots. We need robots that are more user friendly and easier to understand and a key aspect of this is human-like movements and behavior. This project targets a specific set of motions called locomotion and tests them on the humanoid NAO robot. A human-like crawling gait was developed for the NAO robot and compared to the built-in walking gait through three kinds of experiments. The first one to compare the speed of the two gaits, the second one to estimate their sta- bility, and the third to examine how long they can operate by measuring the power consumption and temperatures in the joints. The results showed the robot was significantly slower when crawling compared to walking, and when still the robot was more stable while standing than on all-fours. The power consumption remained essentially the same, but the crawling gait ended up having a shorter operational time due to higher temperature increase in the joints. While the crawling gait has benefits of having a lower profile then the walking gait and could therefore more easily pass under low hanging obsta- cles, it does have major issues that needs to be addressed to become a viable solution. Therefore these are important factors to consider when developing gaits and designing robots, and motives further research to try and solve these problems.