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RML63 Series Parameters and D-H Model

Basic Parameters

Parameter NameParameter Value
Basic ParametersDegrees of Freedom6
ConfigurationHumanoid Configuration
Joint Brake TypeJoints 1 to 4: Hard Brake
Joints 5 to 6: Soft Brake
Working Radius/mmStandard Version: 900
Six-Axis Force L Version: 917
Six-Axis Force K Version: 928.5
Payload/kg3
Self-weight/kgStandard Version: 10
Six-Axis Force Version: 10.1
Repeatability/mm±0.05
TCP Line Speed/m/s≤2.8
Typical Power/W≤100
Peak Power/W≤200
Installation AngleAny Angle
Base Dimensions/mmφ107
MaterialAluminum Alloy/ABS
Environmental AdaptabilityOperating Temperature/℃0-45
Operating Humidity25~85% Non-condensing
Protection LevelBody IP54
Motion Angle Range/°J1-178~+178
J2-178~+178
J3-178~+145
J4-178~+178
J5-178~+178
J6-360~+360
Maximum Angular Velocity/°/sJ1180
J2180
J3225
J4225
J5225
J6225
Force Control Specifications (Supported only by 6-DoF sensors)Six-Axis Force Range200N/7N·m
Six-Axis Force Accuracy±0.5%FS

Ontology Parameters

MDH model frame:

MDH parameters of RML63 (modified D-H parameters):

Joint No.(i)ai1(mm)αi1(°)di(mm)θi / offseti(°)
100d10
2-86-900-90
33800090
469904050
50-900180
60-90d6180
  • RML63II       : d1=172 mm
  • RML63III      : d1=162.5 mm
  • RML63-B     : d6=115.1 mm
  • RML63-6FB : d6=132.3 mm
  • RML63-6F   : d6=143.6 mm

Note:

  • offset refers to the offset of the joint zero position from the model zero position, that is, model angle = joint angle + offset.
  • The RML63 series robotic arm comes in two versions, Type II and Type III, with the main difference being the length of joint 1.

RML63II:

joint_id(i)123456--
m1.8372.0061.9611.2011.0260.1070.2480.189
x-68.442166.733.3990-0.031-0.506-0.426-0.352
y-23.913-0.002-29.498-35.17730.1460.2550.237-0.067
z-6.938-92.59-17.697-184.4-12.341-10.801-27.223-18.302
Lxx3462.12918664.8336432.81953007.5632732.46650.918308.844133.613
Lxy-3765.305-0.5873869.875-0.04-2.123-3.136-3.7810.522
Lxz-46.20630804.1417.6070.0870.374-0.699-1.4681.623
Lyy12643.164103568.4837094.21650754.293829.79347.42304.616130.260
Lyz-50.044-0.287-17.611-5089.754-2.2880.3880.8880.531
Lzz13576.75886722.5599257.0632874.6312384.32360.35122.6289.503
RemarksB6F6FB

RML63III:

joint_id(i)123456--
m1.5982.9901.3571.8641.0230.1070.2480.189
x-12.900109.80014.100-0.1000.100-0.506-0.426-0.352
y0.1000.100-5.600-23.00032.6000.2550.237-0.067
z-29.800-64.200-29.400-236.200-15.200-10.801-27.223-18.302
Lxx3150.72416728.1883116.708128352.3803299.43950.918308.844133.613
Lxy-18.047-17.784508.850-4.255-1.019-3.136-3.7810.522
Lxz-13.56426077.237-1.031-52.2730.0317-0.699-1.4681.623
Lyy4867.960102753.0874083.881125960.7771008.18647.42304.616130.260
Lyz6.61212.6083.755-4630.0830.3360.3880.8880.531
Lzz2833.69188450.0852455.2323681.8842745.43660.35122.6289.503
RemarksB6F6FB

Description:

  • m is the mass of the link, kg
  • x is the x-coordinate of the center of mass of link, mm
  • y is the y-coordinate of the center of mass of link, mm
  • z is the z-coordinate of the center of mass of link, mm
  • Lxx,Lxy,Lxz,Lyy,Lyz,Lzz is the principal moment of inertia described in the link frame, kg·mm²
  • B: standard version, 6FB: Six-Axis Force L Version, 6F: six-axis force K version

Remarks:

  • Source of data: CAD design values.
  • If the inertial parameters in the center of mass frame are required, they can be calculated based on the parallel axis theorem, as stated below.

Assuming there is an output frame {i}, the center of mass frame coinciding with this coordinate system {i} is {c}, and the coordinates of the center of mass in this frame {i} are Pc=[xc,yc,zc]T, then according to the parallel axis theorem:

Ic=Lim(PcTPcI3×3PcPcT)

Where,

Li=[LxxLxyLxzLxyLyyLyzLxzLyzLzz]

Distribution and dimensions of joints

The RML63-B humanoid robotic arm has six rotating joints, each of which represents one degree of freedom. As shown in the figure below, robot joints include the shoulders (joint 1 and joint 2), elbow (joint 3), and wrists (joint 4, joint 5, and joint 6).

alt text

RML63II-B

alt text

RML63III-B

Workspace

The workspace of RML63-B is a sphere with a working radius of 900 mm, in addition to the cylindrical space directly above and below the base. When determining the installation position of the robot, due considerations must be given to the cylindrical space directly above and below the robot, to avoid moving tools to this cylindrical space as much as possible. Furthermore, in actual applications, the motion ranges of all joints are as follows: joint 1: ±178°; joint 2: ±178°; joint 3: -178° to +145°; joint 4: ±178°; joint 5: ±178°; joint 6: ±360°.

alt text

Illustration of space within the reach of robot

Motion singularities

Shoulder singularity

The center of the wrist lies on a plane that passes through the axis of Joint 1 and is parallel to the axis of Joint 2. The exemplary position is [0,-34.85,72.738,0,-35,0], as shown in the figure below:

Shoulder singularity

Shoulder singularity
Elbow singularity

The center of the wrist lies on the plane formed by Joints 2 and 3. The exemplary position is [0,-60,-9.684,0,-90,0], as shown in the figure below: image.png

Elbow Singularity

Elbow Singularity
Wrist singularity

Co-axis of joint 4 and joint 6, q5=0, i.e. the point format is [x,x,x,x,0,x], indicated point [0,60,30,0,0,0], as shown in the figure below:

Wrist singularity

Wrist singularity
Boundary singularity

The end of robotic arm reaches the farthest end (a special situation of q3=-9.683), i.e. the point format is [x,x,-9.683,x,0,x], Indicated points [0,0,-9.683,0,0,0], [-90,-45,-9.683,0,0,0], and [-90,-90,-9.683,0,0,0] as shown in the figure below:

Boundary singularity 1

Boundary singularity 1

Boundary singularity 2

Boundary singularity 2

Boundary singularity 3

Boundary singularity 3

Load curves

Represent the end load curves of RML63-B and RML63-6F and RML63-6FB. Where, L refers to the radial distance of the center of mass of end load against the plane of end flange, and Z refers to the normal distance of the center of mass of end load against the plane of end flange.

RML63-B

End load curves of RML63-B

RML63-6F

End load curves of RML63-6F

RML63-6FB

End load curves of RML63-6FB