Dual Robot Log Handling

The goal of the project is to design end effectors and program 2 6-axis robots to pick up, rotate, and manipulate a log through a band saw to cut a log into a cant. The end effectors will bolt to the 6th axis of each robot and secure the log by penetrating the wood at each end. The cutting planes for each log will be determined by an optimized scan and communicated to the robots via a Programmable Logic controller. In the first year of the project, our goal is to complete the end effector design and program the robots to cut a single face of the cant.

=Project Value= In modern sawmills, logs are cut into lumber through a massive automated assembly line of hydraulic equipment, which is expensive to maintain and required extensive computing power. This could be replaced by a two-robot system which can cut logs with greater efficiency and reduced overhead, maintenance, and computing costs.

=Product Requirements=

The end effector must meet the following requirements: The Programmable Logic Controller should perform the following functions: The Robots should be programmed according to the following requirements: The human-machine interface should communicate with the PLC to perform the following functions: Software: Log: End Effector: System: Click this link for more details about Product Requirements. =End Effector Design= The biggest challenges in the end effector design is implementing shock absorption along the log longitudinal axis without compromising bending under the gravity load of the log and while remaining within the strict size requirements. We constructed a couple rapid prototypes to test shock absorption methods of our end effector designs. Our initial method to solving the design challenges was to place springs around the bolts that mount to the robot. We used a wood laser and some inexpensive parts to build the prototype. By mimicking a gravity load with our hands, we found that this design was not feasible because it allowed for too much vertical bending. An image of the prototype can be seen below (will have more pictures).
 * End Effector :
 * Grip the log on its ends, preventing any slip
 * Fit within a 2 by 4 board to avoid being cut by the saw
 * Prevent the robot from being cut by the saw
 * Resistant to wear at the points of contact
 * Have a high stiffness spring mechanism to absorb shock, prevent the robot from detecting a collision during log penetration
 * Strong enough to avoid fracture due to bending
 * Economical to produce, install, and uninstall
 * Programming :
 * Accept data from optimizer as input variables (log length, diameter and height at each log end)
 * Convert input variables into a form the robots can understand
 * Output variables to robots to communicate offset values into a pre-programmed path
 * A baseline program to cut one face of an infinitesimal log
 * Call variables from the PLC to act ass offsets to set the cutting path according to log geometry
 * Start and stop the robots
 * Display errors in the system
 * Troubleshooting feature to edit the PLC program
 * Specifics :
 * The robots we are programming are Fanuc R2000iC 210L Robots via Fanuc's robot simulation software Roboguide.
 * The PLC is programmed via Studio 5000 software.
 * The HMI will be developed with Ignition software.
 * Mechanical parts are designed with SolidWorks
 * Log diameter ranges from 5 to 12 inches
 * Log lengths up to 8 feet
 * Log mass does not exceed 350 kg (larger logs would be at risk of exceeding the maximum robot load of roughly 2 kN).
 * Member should be at least 6 inches long
 * Member should be less than 3.25 inches wide and 1.5 inches tall
 * Spike should penetrate the log no more than 0.5 inches to minimize waste
 * System should be able to rotate a log with an accuracy of ±2°
 * The system should be operational from temperature ranges of -40°C to 110°F
 * Rapid Prototyping :

Next, we moved forward with a design that implemented shock absorption within the end effector member. Each spike is connected to a linear sliding shaft which pushes a spring. To prove the concept of this design, we are planning to 3D print and purchase inexpensive parts and conduct similar hand loading to mimic the weight load of the log. The drawing package of this prototype is seen below (will have more pictures).


 * End Effector :

=PLC Programming=

=Robot Simulation=

=Design Validation=

=Team Members=

=Additional Documentation=


 * Schedule
 * Budget
 * Meeting Minutes
 * PLC Training
 * End Effector Alignment Rapid Prototype Drawing Package
 * Design Validation Plan
 * Team Contract