Forward kinematics is one of the main research fields in robotics, where the goal is to obtain th... more Forward kinematics is one of the main research fields in robotics, where the goal is to obtain the position of a robot’s end-effector from its joint parameters. This work presents a method for achieving this using a recursive algorithm that builds a 3D computational model from the configuration of a robotic system. The orientation of the robot’s links is determined from the joint angles using Euler Angles and rotation matrices. Kinematic links are modeled sequentially, the properties of each link are defined by its geometry, the geometry of its predecessor in the kinematic chain, and the configuration of the joint between them. This makes this method ideal for tackling serial kinematic chains. The proposed method is advantageous due to its theoretical increase in computational efficiency, ease of implementation, and simple interpretation of the geometric operations. This method is tested and validated by modeling a human-inspired robotic mobile manipulator (CHARMIE) in Python.
In this work, a large-scale tactile detection system is proposed, whose development is based on a... more In this work, a large-scale tactile detection system is proposed, whose development is based on a soft structure using Machine Learning and Computer Vision algorithms to map the surface of a forearm sleeve. The current application has a cylindrical design, whose dimensions intend to be like a human forearm or bicep. The model was developed assuming that deformations occur only at one section at a time. The goal for this system is to be coupled with the CHARMIE robot, a collaborative robot for domestic and medical environments. This system allows the contact detection of the entire forearm surface enabling interaction between a Human Being and a robot. A matrix with sections can be configured to present certain functionalities, allowing CHARMIE to detect contact in a particular section, and thus perform a specific behaviour. After building the dataset, an Artificial Neural Network (ANN) was created. This network was called Section Detection Network (SDN), and through Supervised Learn...
This paper describes the design and implementation of a self-balancing two-wheeled robot, the Equ... more This paper describes the design and implementation of a self-balancing two-wheeled robot, the Equilibrist Robot. The system is similar to the classical unstable, non-linear mechanical control problem of an inverted pendulum on a cart. Using the Linear Quadratic Regulator method and PID for state feedback, this paper shows a control algorithm that solves this problem. This control is able to reject disturbances and stabilize the system using a gyroscope. The control algorithm is implemented using Matlab and Cprograming. The Equilibrist manages to stabilize itself in an upright position, reject disturbances and change its position. Index Terms — Inverted Pendulum, Linear Quadratic Regulator, Servo and Regulator Control, Lego Robot.
Fibre lasers are an attractive option for laser micro-welding applications because of their high ... more Fibre lasers are an attractive option for laser micro-welding applications because of their high beam quality which gives a small spot size. In this paper, the results of an investigation into the micro-welding of stainless steel using a 100 W fibre laser are reported. Continuous and pulsed modes of operation were investigated in terms of penetration depth, top bead width and focus position sensitivity. For the continuous mode, penetration depths of 550 µm were obtained at welding speeds of 5 mm/s. When the welding speed was increased to 30 mm/s the penetration depth was still greater than 400 µm. In the pulsed welding mode, the pulse duration and frequency were varied to give duty cycles of 10% and 50%. There was a significant increase in the penetration depth when the pulse duration was less than 0.5 ms (with the 50% duty cycle) due to the pulse enhancement of the laser at the very short pulse durations. At the same time, the top bead width reduced by over 50% for the lowest pulse...
This paper briefly describes the development of a mobile robot to participate on RoboCup@ Home. T... more This paper briefly describes the development of a mobile robot to participate on RoboCup@ Home. The focus of this project is to integrate robotic knowledge into home applications and human interaction. The robot has the ability to move in all directions due to its ...
The future of robotics is now trending for home servicing. Nursing homes and assistance to elder ... more The future of robotics is now trending for home servicing. Nursing homes and assistance to elder people are areas where robots can provide valuable help in order to improve the quality of life of those who need it most. Calling a robot, for a person of age, can be a daunting task if the voice is failing and any resort to battery operated devices fails to comply. Using a simple mechanical apparatus, such as a Click trainer for dogs, a person can call a robot by pressing the button of a powerless device. The high pitch sound produced by this device can be captured and tracked down in order to estimate the person's location within a room. This paper describes a method that provides good accuracy and uses simple and low cost technology, in order to provide an efficient positional value for an assistance robot to attend its caller. The robot does not need to search for the person in a room as it can directly travel towards the Click's sound source.
The global population is ageing at an unprecedented rate. With changes in life expectancy across ... more The global population is ageing at an unprecedented rate. With changes in life expectancy across the world, three major issues arise: an increasing proportion of senior citizens; cognitive and physical problems progressively affecting the elderly; and a growing number of single-person households. The available data proves the ever-increasing necessity for efficient elderly care solutions such as healthcare service and assistive robots. Additionally, such robotic solutions provide safe healthcare assistance in public health emergencies such as the SARS-CoV-2 virus (COVID-19). CHARMIE is an anthropomorphic collaborative healthcare and domestic assistant robot capable of performing generic service tasks in non-standardised healthcare and domestic environment settings. The combination of its hardware and software solutions demonstrates map building and self-localisation, safe navigation through dynamic obstacle detection and avoidance, different human-robot interaction systems, speech a...
This article describes a solution for a high power controller and actuator of three DC motors in ... more This article describes a solution for a high power controller and actuator of three DC motors in closed loop. This controller can be applied to omnidirectional platform solutions using three motorised Swedish wheels as used by several RobCup MSL robots and Minho omnidirectional Wheelchair. Some existing controllers in the market are reviewed pointing out their characteristics and comparing them with the proposed solution. Operational characteristics and developed algorithms of the proposed system are fully disclosed.
This paper presents the design and implementation of an inverted pendulum and cart. The platform ... more This paper presents the design and implementation of an inverted pendulum and cart. The platform was built by two students under a one semester curricular unit targeted on the design of electronic systems. The developed mechanical parts of the system were designed using CAD software. A PID control algorithm was implemented. Some experimental tests were performed and the corresponding results are presented. Index Terms — Design, Control Application, Inverted Pendulum, Monitoring, PID control.
Forward kinematics is one of the main research fields in robotics, where the goal is to obtain th... more Forward kinematics is one of the main research fields in robotics, where the goal is to obtain the position of a robot’s end-effector from its joint parameters. This work presents a method for achieving this using a recursive algorithm that builds a 3D computational model from the configuration of a robotic system. The orientation of the robot’s links is determined from the joint angles using Euler Angles and rotation matrices. Kinematic links are modeled sequentially, the properties of each link are defined by its geometry, the geometry of its predecessor in the kinematic chain, and the configuration of the joint between them. This makes this method ideal for tackling serial kinematic chains. The proposed method is advantageous due to its theoretical increase in computational efficiency, ease of implementation, and simple interpretation of the geometric operations. This method is tested and validated by modeling a human-inspired robotic mobile manipulator (CHARMIE) in Python.
In this work, a large-scale tactile detection system is proposed, whose development is based on a... more In this work, a large-scale tactile detection system is proposed, whose development is based on a soft structure using Machine Learning and Computer Vision algorithms to map the surface of a forearm sleeve. The current application has a cylindrical design, whose dimensions intend to be like a human forearm or bicep. The model was developed assuming that deformations occur only at one section at a time. The goal for this system is to be coupled with the CHARMIE robot, a collaborative robot for domestic and medical environments. This system allows the contact detection of the entire forearm surface enabling interaction between a Human Being and a robot. A matrix with sections can be configured to present certain functionalities, allowing CHARMIE to detect contact in a particular section, and thus perform a specific behaviour. After building the dataset, an Artificial Neural Network (ANN) was created. This network was called Section Detection Network (SDN), and through Supervised Learn...
This paper describes the design and implementation of a self-balancing two-wheeled robot, the Equ... more This paper describes the design and implementation of a self-balancing two-wheeled robot, the Equilibrist Robot. The system is similar to the classical unstable, non-linear mechanical control problem of an inverted pendulum on a cart. Using the Linear Quadratic Regulator method and PID for state feedback, this paper shows a control algorithm that solves this problem. This control is able to reject disturbances and stabilize the system using a gyroscope. The control algorithm is implemented using Matlab and Cprograming. The Equilibrist manages to stabilize itself in an upright position, reject disturbances and change its position. Index Terms — Inverted Pendulum, Linear Quadratic Regulator, Servo and Regulator Control, Lego Robot.
Fibre lasers are an attractive option for laser micro-welding applications because of their high ... more Fibre lasers are an attractive option for laser micro-welding applications because of their high beam quality which gives a small spot size. In this paper, the results of an investigation into the micro-welding of stainless steel using a 100 W fibre laser are reported. Continuous and pulsed modes of operation were investigated in terms of penetration depth, top bead width and focus position sensitivity. For the continuous mode, penetration depths of 550 µm were obtained at welding speeds of 5 mm/s. When the welding speed was increased to 30 mm/s the penetration depth was still greater than 400 µm. In the pulsed welding mode, the pulse duration and frequency were varied to give duty cycles of 10% and 50%. There was a significant increase in the penetration depth when the pulse duration was less than 0.5 ms (with the 50% duty cycle) due to the pulse enhancement of the laser at the very short pulse durations. At the same time, the top bead width reduced by over 50% for the lowest pulse...
This paper briefly describes the development of a mobile robot to participate on RoboCup@ Home. T... more This paper briefly describes the development of a mobile robot to participate on RoboCup@ Home. The focus of this project is to integrate robotic knowledge into home applications and human interaction. The robot has the ability to move in all directions due to its ...
The future of robotics is now trending for home servicing. Nursing homes and assistance to elder ... more The future of robotics is now trending for home servicing. Nursing homes and assistance to elder people are areas where robots can provide valuable help in order to improve the quality of life of those who need it most. Calling a robot, for a person of age, can be a daunting task if the voice is failing and any resort to battery operated devices fails to comply. Using a simple mechanical apparatus, such as a Click trainer for dogs, a person can call a robot by pressing the button of a powerless device. The high pitch sound produced by this device can be captured and tracked down in order to estimate the person's location within a room. This paper describes a method that provides good accuracy and uses simple and low cost technology, in order to provide an efficient positional value for an assistance robot to attend its caller. The robot does not need to search for the person in a room as it can directly travel towards the Click's sound source.
The global population is ageing at an unprecedented rate. With changes in life expectancy across ... more The global population is ageing at an unprecedented rate. With changes in life expectancy across the world, three major issues arise: an increasing proportion of senior citizens; cognitive and physical problems progressively affecting the elderly; and a growing number of single-person households. The available data proves the ever-increasing necessity for efficient elderly care solutions such as healthcare service and assistive robots. Additionally, such robotic solutions provide safe healthcare assistance in public health emergencies such as the SARS-CoV-2 virus (COVID-19). CHARMIE is an anthropomorphic collaborative healthcare and domestic assistant robot capable of performing generic service tasks in non-standardised healthcare and domestic environment settings. The combination of its hardware and software solutions demonstrates map building and self-localisation, safe navigation through dynamic obstacle detection and avoidance, different human-robot interaction systems, speech a...
This article describes a solution for a high power controller and actuator of three DC motors in ... more This article describes a solution for a high power controller and actuator of three DC motors in closed loop. This controller can be applied to omnidirectional platform solutions using three motorised Swedish wheels as used by several RobCup MSL robots and Minho omnidirectional Wheelchair. Some existing controllers in the market are reviewed pointing out their characteristics and comparing them with the proposed solution. Operational characteristics and developed algorithms of the proposed system are fully disclosed.
This paper presents the design and implementation of an inverted pendulum and cart. The platform ... more This paper presents the design and implementation of an inverted pendulum and cart. The platform was built by two students under a one semester curricular unit targeted on the design of electronic systems. The developed mechanical parts of the system were designed using CAD software. A PID control algorithm was implemented. Some experimental tests were performed and the corresponding results are presented. Index Terms — Design, Control Application, Inverted Pendulum, Monitoring, PID control.
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Papers by Gil Lopes