CURSO-2006 1.1 Topics about of Topics about of design and design and construction of construction of experimental parallel experimental parallel robots in DISAM robots in DISAM (based on examples) (based on examples) Roque Saltaren Universidad Politécnica de Madrid, SPAIN [email protected]
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CURSO-20061.1 Topics about of design and construction of experimental parallel robots in DISAM (based on examples) Roque Saltaren Universidad Politécnica.
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CURSO-2006 1.1
Topics about of design and Topics about of design and construction of experimental construction of experimental parallel robots in DISAM parallel robots in DISAM (based on examples)(based on examples)
Roque Saltaren Universidad Politécnica de Madrid, SPAIN
1. Relevant characteristics of some parallel robots develops for biomechanics applications
2. Kinematics modeling and design considerations3. Dynamics modeling and design considerations4. Mechanical design and construction5. Hardware and control
Hardware architecture based on PC-104/PowerPC + LAN
Hardware architecture based on multiaxis card Hardware architecture based on dSPACE
6. User interfaces7. Real time operative systems (RTOS).8. Integration9. Conclusions: Real prototypes or scale prototypes:
..Kinematics modeling and design consideration..Kinematics modeling and design consideration
Two problematic aspects: Singularities (restrictions
over the work space!!) Don’t forget the theory!
(Hunt, Fletcher, Di-Gregory, etc.)
Modeling with screw based jacobian
Path planning control in base to the Conditioning Index CI, and Global Conditioning Index GCI
Direct kinematics solution: Numerical methods
based on multibody mechanics and Newton-Raphson methods!!
Design considerations: GCI index very useful to
know and understand the machine
1.18Universidad Politécnica de Madrid
……Dynamics modeling and design considerationsDynamics modeling and design considerations
For a Stewart-Gough platform: Dynamics modeling:
Multibody dynamics: we are use two ways:1. Programming with ADAMS
(after of know how program with ADAMS, very fast develops!) the problem is that the ADAMS language is not easy!!
2. Programming with Matlab: Is better, but is necessary to have a very good acknowledges on multibody dynamics!! and to have some experts in the group!
3. For real time RT, we works in multibody dynamics for RT: we used OOD, C++ + UML + RTLinux.
1.19Universidad Politécnica de Madrid
Mechanical design and constructionMechanical design and construction
The first prototype: Is necessary to have a PERFECT first experimental prototype??. Usually not!!
In many occasion we need first demonstrate some hypothesis!
In many occasion we need allows that the control and software run!
Really we need a prototype in real scale?? Not, we are sure that in many occasions to
demonstrate the hypothesis and develop computational algorithms is sufficiently to work with scaleable prototypes!!.
1.20Universidad Politécnica de Madrid
……Mechanical design and constructionMechanical design and construction
A case. We are developing an underwater parallel
robot We should optimized the useful internal space to
assembly the control and power hardware, because this:
The geometrical form of the robot hull is very complicated
The length of the hull is diffuse because we will need aggregate more hardware in the future
The machining costs can be high if we used an adjusted geometry to the hardware dimensions
1.21Universidad Politécnica de Madrid
……Mechanical design and constructionMechanical design and construction
The solution adopted. We decide use an engineering
plastic with non-hygroscopic performance, soldering and adhesive good properties (many plastics can not solder!!)
The plastic selected is appropriate to machining (for example, we can use joints with mechanical screws)
We use Delrin Acetal plastic (Du Pont)
The plastic weight 1/8 part of the steel!!
The design limit the machining to 2 ½ D
The design is modular We can use adhesives Machining with water jet cutting Assembly with mechanical
screws + GORE Tex seals and adhesives
1.22Universidad Politécnica de Madrid
Hardware and controlHardware and control
In many applications is sufficiently with the next hardware architecture: Based on PC-104 + RS 485
LAN + Ethernet Multiaxis control base on
multipoint RS-485 Duplex Network to 115200 Bps.
Capacity to control many axis (256)
Develop below QNX real time system or RT Linux
Flash SD memory (2 G) And the better!!: less of 1000
eur We used this card to control a S-G
parallel robot with 12 Step servomotors.
We used Stepper motors to avoid used encoder and its electric cables
The servomotors power and control hardware are prepared to connect in Network (Duplex RS-485) !!!
PC compatible Single Board Computer with 133 MHz AMD 586 processor.32-64 MB SDRAM 10/100 Ethernet PCMCIA socket Compact Flash socket Optional A/D & DAC 2 COM ports 23 DIO PC/104 expansion bus 2 MB Flash drive Technologic Systems, Incorporated16610 East Laser Drive, Suite 10Fountain Hills, AZ 85268480-837-5200FAX [email protected]://www.embeddedx86.com/