Delta robot

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Delta robot of the FlexPicker series by ABB Robot delta FlexPicker d'ABB.png
Delta robot of the FlexPicker series by ABB

Sketchy, a portrait-drawing delta robot Sketchy, portrait-drawing delta robot.jpg
Sketchy, a portrait-drawing delta robot

A delta robot is a type of parallel robot [2] that consists of three arms connected to universal joints at the base. The key design feature is the use of parallelograms in the arms, which maintains the orientation of the end effector. [3] In contrast, a Stewart platform can change the orientation of its end effector. [3]

Contents

Delta robots have popular usage in picking and packaging in factories because they can be quite fast, some executing up to 300 picks per minute. [4]

History

Commercial pick and place robots TOSY Parallel Robot.JPG
Commercial pick and place robots

The delta robot (a parallel arm robot) was invented in the early 1980s by a research team led by professor Reymond Clavel at the École Polytechnique Fédérale de Lausanne (EPFL, Switzerland). [5] After a visit to a chocolate maker, a team member wanted to develop a robot to place pralines in their packages. [6] The purpose of this new type of robot was to manipulate light and small objects at a very high speed, an industrial need at that time.

In 1987, the Swiss company Demaurex purchased a license for the delta robot and started the production of delta robots for the packaging industry. In 1991, Reymond Clavel presented his doctoral thesis 'Conception d'un robot parallèle rapide à 4 degrés de liberté', [7] and received the golden robot award in 1999 for his work and development of the delta robot. Also in 1999, ABB Flexible Automation started selling its delta robot, the FlexPicker. By the end of 1999, delta robots were also sold by Sigpack Systems.

In 2017, researchers from Harvard's Microrobotics Lab miniaturized it with piezoelectric actuators to 0.43 grams for 15 mm x 15 mm x 20 mm, capable of moving a 1.3 g payload around a 7 cubic millimeter workspace with a 5 micrometers precision, reaching 0.45 m/s speeds with 215 m/s² accelerations and repeating patterns at 75 Hz. [8]

Design

Delta robot kinematics (green arms are fixed length, at 90deg to their blue axis that they rotate about) DeltaRamki.gif
Delta robot kinematics (green arms are fixed length, at 90° to their blue axis that they rotate about)
Over-actuated planar delta robot. Planar DELTA robot.gif
Over-actuated planar delta robot.

The delta robot is a parallel robot, i.e. it consists of multiple kinematic chains connecting the base with the end-effector. The robot can also be seen as a spatial generalisation of a four-bar linkage. [9]

The key concept of the delta robot is the use of parallelograms which restrict the movement of the end platform to pure translation, i.e. only movement in the X, Y or Z direction with no rotation.

The robot's base is mounted above the workspace and all the actuators are located on it. From the base, three middle jointed arms extend. The ends of these arms are connected to a small triangular platform. Actuation of the input links will move the triangular platform along the X, Y or Z direction. Actuation can be done with linear or rotational actuators, with or without reductions (direct drive).

Since the actuators are all located in the base, the arms can be made of a light composite material. As a result of this, the moving parts of the delta robot have a small inertia. This allows for very high speed and high accelerations. Having all the arms connected together to the end-effector increases the robot stiffness, but reduces its working volume.

The version developed by Reymond Clavel has four degrees of freedom: [7] three translations and one rotation. In this case a fourth leg extends from the base to the middle of the triangular platform giving to the end effector a fourth, rotational degree of freedom around the vertical axis.

Currently other versions of the delta robot have been developed:

The majority of delta robots use rotary actuators. Vertical linear actuators have recently been used (using a linear delta design) to produce a novel design of 3D printer. [13] [14] These offer advantages over conventional leadscrew-based 3D printers of quicker access to a larger build volume for a comparable investment in hardware.

Applications

Large delta-style 3D printer Large delta-style 3D printer.jpg
Large delta-style 3D printer

Industries that take advantage of the high speed of delta robots are the food, pharmaceutical and electronics industry. [16] [17] For its stiffness it is also used for surgery, in particular, the Surgiscope is a delta robot used as a microscopic holder system. [18]

The structure of a delta robot can also be used to create haptic controllers. [19] More recently, the technology has been adapted to 3D printers. [20]

Related Research Articles

<span class="mw-page-title-main">Industrial robot</span> Robot used in manufacturing

An industrial robot is a robot system used for manufacturing. Industrial robots are automated, programmable and capable of movement on three or more axes.

An actuator is a component of a machine that produces force, torque, or displacement, usually in a controlled way, when an electrical, pneumatic or hydraulic input is supplied to it in a system. An actuator converts such an input signal into the required form of mechanical energy. It is a type of transducer. In simple terms, it is a "mover".

<span class="mw-page-title-main">Gimbal lock</span> Loss of one degree of freedom in a three-dimensional, three-gimbal mechanism

Gimbal lock is the loss of one degree of freedom in a multi-dimensional mechanism at certain alignments of the axes. In a three-dimensional three-gimbal mechanism, gimbal lock occurs when the axes of two of the gimbals are driven into a parallel configuration, "locking" the system into rotation in a degenerate two-dimensional space.

<span class="mw-page-title-main">Stewart platform</span> Type of parallel manipulator

A Stewart platform is a type of parallel manipulator that has six prismatic actuators, commonly hydraulic jacks or electric linear actuators, attached in pairs to three positions on the platform's baseplate, crossing over to three mounting points on a top plate. All 12 connections are made via universal joints. Devices placed on the top plate can be moved in the six degrees of freedom in which it is possible for a freely-suspended body to move: three linear movements x, y, z, and the three rotations.

<span class="mw-page-title-main">Inverse kinematics</span> Computing joint values of a kinematic chain from a known end position

In computer animation and robotics, inverse kinematics is the mathematical process of calculating the variable joint parameters needed to place the end of a kinematic chain, such as a robot manipulator or animation character's skeleton, in a given position and orientation relative to the start of the chain. Given joint parameters, the position and orientation of the chain's end, e.g. the hand of the character or robot, can typically be calculated directly using multiple applications of trigonometric formulas, a process known as forward kinematics. However, the reverse operation is, in general, much more challenging.

<span class="mw-page-title-main">Cartesian coordinate robot</span> Robot with axes of control that are linear and orthogonal

A Cartesian coordinate robot is an industrial robot whose three principal axes of control are linear and are at right angles to each other. The three sliding joints correspond to moving the wrist up-down, in-out, back-forth. Among other advantages, this mechanical arrangement simplifies the robot control arm solution. It has high reliability and precision when operating in three-dimensional space. As a robot coordinate system, it is also effective for horizontal travel and for stacking bins.

<span class="mw-page-title-main">Robot kinematics</span> Geometric analysis of multi-DoF kinematic chains that model a robot

In robotics, robot kinematics applies geometry to the study of the movement of multi-degree of freedom kinematic chains that form the structure of robotic systems. The emphasis on geometry means that the links of the robot are modeled as rigid bodies and its joints are assumed to provide pure rotation or translation.

<span class="mw-page-title-main">Six degrees of freedom</span> Types of movement possible for a rigid body in three-dimensional space

Six degrees of freedom (6DOF), or sometimes six degrees of movement, refers to the six mechanical degrees of freedom of movement of a rigid body in three-dimensional space. Specifically, the body is free to change position as forward/backward (surge), up/down (heave), left/right (sway) translation in three perpendicular axes, combined with changes in orientation through rotation about three perpendicular axes, often termed yaw, pitch, and roll.

<span class="mw-page-title-main">Ballbot</span> Mobile robot design

A ball balancing robot also known as a ballbot is a dynamically-stable mobile robot designed to balance on a single spherical wheel. Through its single contact point with the ground, a ballbot is omnidirectional and thus exceptionally agile, maneuverable and organic in motion compared to other ground vehicles. Its dynamic stability enables improved navigability in narrow, crowded and dynamic environments. The ballbot works on the same principle as that of an inverted pendulum.

<span class="mw-page-title-main">Serial manipulator</span>

Serial manipulators are the most common industrial robots and they are designed as a series of links connected by motor-actuated joints that extend from a base to an end-effector. Often they have an anthropomorphic arm structure described as having a "shoulder", an "elbow", and a "wrist".

<span class="mw-page-title-main">Parallel manipulator</span>

A parallel manipulator is a mechanical system that uses several computer-controlled serial chains to support a single platform, or end-effector. Perhaps, the best known parallel manipulator is formed from six linear actuators that support a movable base for devices such as flight simulators. This device is called a Stewart platform or the Gough-Stewart platform in recognition of the engineers who first designed and used them.

In classical mechanics, a kinematic pair is a connection between two physical objects that imposes constraints on their relative movement (kinematics). German engineer Franz Reuleaux introduced the kinematic pair as a new approach to the study of machines that provided an advance over the motion of elements consisting of simple machines.

<span class="mw-page-title-main">Robotic arm</span> Type of mechanical arm with similar functions to a human arm.

A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human arm; the arm may be the sum total of the mechanism or may be part of a more complex robot. The links of such a manipulator are connected by joints allowing either rotational motion or translational (linear) displacement. The links of the manipulator can be considered to form a kinematic chain. The terminus of the kinematic chain of the manipulator is called the end effector and it is analogous to the human hand. However, the term "robotic hand" as a synonym of the robotic arm is often proscribed.

<span class="mw-page-title-main">Glossary of robotics</span> List of definitions of terms and concepts commonly used in the study of robotics

Robotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture and application of robots. Robotics is related to the sciences of electronics, engineering, mechanics, and software.

<span class="mw-page-title-main">Mechanism (engineering)</span> Device used to transfer forces via non-electric means

In engineering, a mechanism is a device that transforms input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components which may include:

The following outline is provided as an overview of and topical guide to robotics:

<span class="mw-page-title-main">Reymond Clavel</span>

Reymond Clavel is director of the Laboratoire de Systèmes Robotiques 2 (LSRO2) at the École Polytechnique Fédérale de Lausanne in Switzerland. He is one of the pioneers in the development of parallel robots, and the inventor of the notable Delta robot. His interest in research and his teaching are related mostly to robotics, micro-robotics and high precision mechanisms. His main domains of expertise are:

<span class="mw-page-title-main">Five-bar linkage</span> 2-DoF mechanism with 5 links and 5 joints

In kinematics, a five-bar linkage is a mechanism with two degrees of freedom that is constructed from five links that are connected together in a closed chain. All links are connected to each other by five joints in series forming a loop. One of the links is the ground or base. This configuration is also called a pantograph, however, it is not to be confused with the parallelogram-copying linkage pantograph.

<span class="mw-page-title-main">High performance positioning system</span> Industrial Engineering method

A high performance positioning system (HPPS) is a type of positioning system consisting of a piece of electromechanics equipment (e.g. an assembly of linear stages and rotary stages) that is capable of moving an object in a three-dimensional space within a work envelope. Positioning could be done point to point or along a desired path of motion. Position is typically defined in six degrees of freedom, including linear, in an x,y,z cartesian coordinate system, and angular orientation of yaw, pitch, roll. HPPS are used in many manufacturing processes to move an object (tool or part) smoothly and accurately in six degrees of freedom, along a desired path, at a desired orientation, with high acceleration, high deceleration, high velocity and low settling time. It is designed to quickly stop its motion and accurately place the moving object at its desired final position and orientation with minimal jittering.

In robotics, Cartesian parallel manipulators are manipulators that move a platform using parallel-connected kinematic linkages ('limbs') lined up with a Cartesian coordinate system. Multiple limbs connect the moving platform to a base. Each limb is driven by a linear actuator and the linear actuators are mutually perpendicular. The term 'parallel' here refers to the way that the kinematic linkages are put together, it does not connote geometrically parallel; i.e., equidistant lines.

References

  1. "Sketchy, a home-constructed drawing robot". Jarkman.
  2. Bonev, I. (2001) Delta Parallel Robot — the Story of Success, Online article available at http://www.parallemic.org/Reviews/Review002.html
  3. 1 2 Bonev, I. The True Origins of Parallel Robots. Online article available at http://www.parallemic.org/Reviews/Review007.html
  4. "Robotics News & Articles".
  5. US 4976582,Clavel, Reymond,"Device for the movement and positioning of an element in space",published 1990-12-11, assigned to Sogeva SA
  6. Laure-Anne Pessina (7 March 2012). "Reymond Clavel, creator of the Delta Robot reflects on his career". EPFL. Archived from the original on 27 October 2018. Retrieved 19 January 2018.
  7. 1 2 Clavel, R. (1991) Conception d'un robot parallèle rapide à 4 degrés de liberté. PhD Thesis, EPFL, Lausanne, Switzerland
  8. Evan Ackerman (17 January 2018). "Harvard's milliDelta Robot Is Tiny and Scary Fast". IEEE Spectrum.
  9. Merlet, J.-P., Parallel Robots, Kluwer Academic Publishers, 2000.
  10. Miller, K., "Modeling of Dynamics and Model-Based Control of DELTA Direct-Drive Parallel Robot," Journal of Robotics and Mechatronics, Vol. 17, No. 4, pp. 344-352, 1995.
  11. "Gallery of robots - prof. Reymond Clavel"
  12. Reymond CLAVEL. "Robots parallèles" Archived 20 September 2018 at the Wayback Machine
  13. Johann Rocholl (6 February 2012). "Rostock (delta robot 3D printer)". Thingiverse.
  14. Mike Szczys (13 July 2012). "3D printing with a delta robot that seems to simplify the concept".
  15. "Hoosier Daddy – The Largest Delta 3D Printer in the World". 3D Printer World. Punchbowl Media. 23 July 2014. Archived from the original on 26 October 2014. Retrieved 28 September 2014.
  16. "Delta Parallel Robot - the Story of Success". www.parallemic.org. Retrieved 30 December 2023.
  17. "New Delta Robots Handle Primary Food Packaging". Packaging World. 1 August 2022. Retrieved 30 December 2023.
  18. Deblaise, D.; Maurine, P. (2005). Effective geometrical calibration of a delta parallel robot used in neurosurgery. pp. 1313–1318. doi:10.1109/iros.2005.1545081. ISBN   0-7803-8912-3. S2CID   17649458 . Retrieved 30 December 2023.
  19. Sunny Bains (8 August 2007). "Feeling virtual worlds".
  20. Carabin, G.; Scalera, L.; Wongratanaphisan, T.; Vidoni, R. (2021). "An energy-efficient approach for 3D printing with a Linear Delta Robot equipped with optimal springs". Robotics and Computer-Integrated Manufacturing. 67: 102045. doi:10.1016/j.rcim.2020.102045. S2CID   224881163.