如何在不破坏关节的情况下增加Revolute关节的扭矩？

Question

我想在BOX-2D中制作一个可以轻松弯曲的柔性杆（如钢尺）。杆的一端是固定的，通过弯曲和释放另一端，我想击球。为此，我使用了许多小体来制作杆，这些小体体通过旋转接头相互连接。然后我用鼠标关节弯曲它。但问题是，在释放它以击晕球之后，我没有获得足够的力量。即使我增加了关节的扭矩，构成杆的物体也会破裂。有没有办法增加力量，还是我应该采用另一种方法制造杆？这是我用来制作杆的代码。

////creating base body...... 
b2BodyDef bodydef_base_2;
bodydef_base_2.type = b2_staticBody;
bodydef_base_2.position.Set(400.0f/PTM_RATIO,(FLOOR_HEIGHT-50)/PTM_RATIO);
b2Body * body_stat_base_2 = world->CreateBody(& bodydef_base_2);     
b2FixtureDef bodyboxDef_base_2;
bodydef_base_2.bullet=true;
b2PolygonShape polygon_body_base_2;
polygon_body_base_2.SetAsBox(.4, .1);
bodyboxDef_base_2.shape = &polygon_body_base_2;
bodyboxDef_base_2.density = 1.0f;        
b2Fixture * jointfixture_base_2 = body_stat_base_2->CreateFixture(&bodyboxDef_base_2);

////////creating the rod with bodies and joints...   
for (int i = 0; i<body_number; i++) {   

    sp_2[i] = [CCSprite spriteWithFile:@"1.png"];
    [self addChild:sp_2[i]];
    sp_2[i].position =ccp(180.0f/PTM_RATIO,(FLOOR_HEIGHT+50+4*i)/PTM_RATIO);
    bodydef_2.type = b2_dynamicBody;
    bodydef_2.position.Set(400.0f/PTM_RATIO,(FLOOR_HEIGHT+50+4*i-50)/PTM_RATIO);
    // bodydef.userData = sp[i];
    body_2[i] = world->CreateBody(& bodydef_2);     
    bodyboxDef_2.shape = &polygon_body_2;
    polygon_body_2.SetAsBox(.04/factor, .2/factor);
    bodyboxDef_2.density = 15.0F;
    bodyboxDef_2.filter.groupIndex = -1;
    jointfixture_2 = body_2[i]->CreateFixture(&bodyboxDef_2);  
    bodydef_2.bullet = true;

    if (i==0) {
        revolutejointdef_2.Initialize(body_stat_base_2, body_2[i], b2Vec2(233.0f/PTM_RATIO, 100/PTM_RATIO)); 
    } else {
        revolutejointdef_2.Initialize(body_2[i-1], body_2[i], b2Vec2(233.0f/PTM_RATIO, 100/PTM_RATIO));
    }

    revolutejointdef_2.collideConnected = true;
    revolutejointdef_2.enableMotor = true;
    revolutejointdef_2.enableLimit = true;
    revolutejointdef_2.motorSpeed  =-5-(body_number-i)*5*0/factor;
    revolutejointdef_2.localAnchorA.Set(.02/factor,.2/factor);
    revolutejointdef_2.localAnchorB.Set(.02/factor,-.2/factor);
    revolutejointdef_2.lowerAngle  = CC_DEGREES_TO_RADIANS(0);
    revolutejointdef_2.upperAngle  = CC_DEGREES_TO_RADIANS(10+i);
    revolutejointdef_2.maxMotorTorque = 0;//+i*.03;
    revolutjoint_2[i] = (b2RevoluteJoint*)world->CreateJoint(&revolutejointdef_2);

    positionarray_2[i] = body_2[i]->GetPosition();

    b2MouseJointDef md;
    md.bodyA = groundBody;
    md.bodyB = body_2[i];
    md.target = posarray_2[i];            
    md.maxForce = 50*i;            
    mouseJoint_2[i] = (b2MouseJoint *)world->CreateJoint(&md);
}